Wafer manufacturing method and laminated device chip manufacturing method

ABSTRACT

A wafer manufacturing method includes a wafer preparing step of preparing a wafer including a semiconductor device formed in each of a plurality of regions demarcated by a plurality of streets intersecting each other, a removing step of removing, from the wafer, a defective device region including a semiconductor device determined to be a defective product among a plurality of the semiconductor devices formed in the wafer, a support substrate fixing step of fixing the wafer to a support substrate, and a fitting step of fitting, into a removed region formed by removing the defective device region from the wafer, a device chip including a semiconductor device as a non-defective product having same functions as those of the semiconductor device determined to be a defective product and having a size capable of being fitted into the removed region, and fixing the device chip to the support substrate.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a method for manufacturing a waferincluding a plurality of semiconductor devices and a method formanufacturing a laminated device chip including a plurality of laminatedsemiconductor devices.

Description of the Related Art

A device chip manufacturing process uses a wafer in which asemiconductor device is formed in each of a plurality of regionsdemarcated by a plurality of streets (planned dividing lines) arrangedin a lattice manner. A plurality of device chips including respectivesemiconductor devices are obtained by dividing the wafer along thestreets. The device chips are incorporated into various electronicapparatuses such as mobile telephones or personal computers.

In recent years, a technology for manufacturing device chips including aplurality of laminated semiconductor devices (laminated device chips)has been put to practical use. The laminated device chips are obtainedby, for example, laminating a plurality of device chips and connectingsemiconductor devices to each other by through electrodes(through-silicon vias (TSV)) that vertically penetrate the device chips.The use of the through electrodes can shorten wiring connecting thesemiconductor devices to each other as compared with a case of usingwire bonding or the like, and can therefore achieve miniaturization ofthe laminated device chips and an improvement in processing speed of thelaminated device chips.

A method referred to as Wafer on Wafer (WoW) has been proposed as amethod for manufacturing the laminated device chips. In this method, alaminated wafer is formed by laminating a plurality of wafers andconnecting semiconductor devices included in the respective wafers toeach other by electrodes formed so as to penetrate the laminated wafers.Then, the laminated device chips are manufactured by dividing thelaminated wafer along the streets.

However, the wafers used to manufacture the laminated device chips mayinclude a defective product of a semiconductor device (defectivedevice). Then, when the laminated wafer formed by laminating the wafersincluding the defective device is divided, the laminated device chipsincluding the defective device are manufactured. When some ofsemiconductor devices included in a laminated device chip are defectiveproducts, the laminated device chip as a whole is determined to be adefective product (defective chip) even if the other semiconductordevices are non-defective products. Therefore, in manufacturing thelaminated device chips, there is a large effect of a decrease in yielddue to defective devices.

Accordingly, before the lamination of a plurality of wafers, aninspection which determines whether semiconductor devices included inthe wafers are each a non-defective product or a defective product isperformed. Then, an optimum combination of wafers used to manufacturelaminated device chips is determined on the basis of the number,arrangement, and the like of defective devices included in the wafers,for example (see Japanese Patent Laid-Open No. 2012-134334). Thus, thenumber of laminated device chips including a defective device isminimized, so that a decrease in yield is suppressed.

SUMMARY OF THE INVENTION

As described above, even when the wafers include defective devices, thenumber of laminated device chips including a defective device (defectivechips) can be minimized by determining a combination of wafers on thebasis of a result of the inspection of the semiconductor devices.However, as long as the wafers include defective devices, at least acertain number of defective chips are manufactured when the laminateddevice chips are manufactured by using the wafers including defectivedevices. There is thus a limit to the reduction of the number ofdefective chips.

The present invention has been made in view of such problems. It is anobject of the present invention to provide a method for manufacturingwafers that can suppress a decrease in yield of laminated device chipsand a method for manufacturing the laminated device chips which methoduses the wafers.

In accordance with an aspect of the present invention, there is provideda wafer manufacturing method including a wafer preparing step ofpreparing a wafer including a semiconductor device formed in each of aplurality of regions demarcated by a plurality of streets intersectingeach other, a removing step of removing, from the wafer, a defectivedevice region including a semiconductor device determined to be adefective product among a plurality of the semiconductor devices formedin the wafer, a support substrate fixing step of fixing the wafer to asupport substrate, after the removing step is performed, and a fittingstep of fitting, into a removed region formed by removing the defectivedevice region from the wafer, a device chip including a semiconductordevice as a non-defective product having same functions as those of thesemiconductor device determined to be a defective product and having asize capable of being fitted into the removed region, and fixing thedevice chip to the support substrate, after the support substrate fixingstep is performed.

Incidentally, preferably, the support substrate fixing step fixes thewafer to the support substrate by an adhesive formed of a thermosettingresin. In addition, preferably, the support substrate has a property oftransmitting ultraviolet rays, and the support substrate fixing stepfixes the wafer to the support substrate by an adhesive formed of anultraviolet curable resin. In addition, preferably, the supportsubstrate fixing step fixes the wafer to the support substrate bypressing the wafer against the support substrate via a sheet notincluding an adhesive while heating the sheet.

In addition, preferably, the wafer manufacturing method further includesa resin filling step of filling a resin into a gap between the devicechip and the wafer, after the fitting step is performed, and a resingrinding step of grinding the resin formed on an outside of the gap,after the resin filling step is performed.

In accordance with another aspect of the present invention, there isprovided a laminated device chip manufacturing method including a waferpreparing step of preparing a first wafer and a second wafer each havinga semiconductor device formed in each of a plurality of regionsdemarcated by a plurality of streets intersecting each other, a removingstep of removing, from the first wafer, a defective device regionincluding a semiconductor device determined to be a defective productamong a plurality of the semiconductor devices formed in the firstwafer, a support substrate fixing step of fixing the first wafer to asupport substrate, after the removing step is performed, a fitting stepof fitting, into a removed region formed by removing the defectivedevice region from the first wafer, a device chip including asemiconductor device as a non-defective product having same functions asthose of the semiconductor device determined to be a defective productand having a size capable of being fitted into the removed region, andfixing the device chip to the support substrate, after the supportsubstrate fixing step is performed, a wafer laminating step of forming alaminated wafer by laminating the second wafer onto the first wafer, anda dividing step of forming laminated device chips including a pluralityof the laminated semiconductor devices by dividing the laminated waferalong the streets.

Incidentally, preferably, the wafer laminating step directly bonds thefirst wafer and the second wafer to each other.

In the wafer manufacturing method according to one aspect of the presentinvention, the defective device region including the semiconductordevice determined to be a defective product is removed from the wafer,and a device chip including a semiconductor device as a non-defectiveproduct is fitted into a gap formed by removing the defective deviceregion. The wafer not including the defective device can be therebymanufactured. In addition, laminated device chips each not including thedefective device can be manufactured by laminating the wafers each notincluding the defective device, thereby forming a laminated wafer, anddividing the laminated wafer. As a result, a decrease in yield of thelaminated device chips is suppressed.

The above and other objects, features and advantages of the presentinvention and the manner of realizing them will become more apparent,and the invention itself will best be understood from a study of thefollowing description and appended claims with reference to the attacheddrawings showing some preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view depicting a wafer;

FIG. 1B is a sectional view depicting the wafer;

FIG. 1C is a perspective view depicting a semiconductor device;

FIG. 2 is a front view depicting a grinding apparatus;

FIG. 3A is a sectional view depicting the wafer in a removing step;

FIG. 3B is a perspective view depicting the wafer in which a throughhole is formed;

FIG. 4A is a sectional view depicting the wafer irradiated with a laserbeam;

FIG. 4B is a sectional view depicting the wafer in which a modifiedlayer is formed;

FIG. 4C is a sectional view depicting a modified layer including aplurality of modified regions;

FIG. 5A is a plan view depicting a path in a quadrangular shape withrounded corners;

FIG. 5B is a plan view depicting a rectangular path;

FIG. 5C is a plan view depicting a plurality of linear paths;

FIG. 6 is a sectional view depicting the wafer after being ground;

FIG. 7A is a sectional view depicting the wafer subjected to plasmaetching;

FIG. 7B is a sectional view depicting the wafer after the plasmaetching;

FIG. 8A is a sectional view depicting the wafer when preprocessing isperformed on an adhesive layer;

FIG. 8B is a sectional view depicting the wafer when a defective deviceregion is separated;

FIG. 9 is a sectional view depicting an ultrasonic irradiating unit;

FIG. 10A is a sectional view depicting the wafer irradiated with a laserbeam;

FIG. 10B is a sectional view depicting the wafer in which a groove isformed;

FIG. 11A is a sectional view depicting the wafer fixed to a supportsubstrate;

FIG. 11B is a sectional view depicting the wafer after being ground;

FIG. 12A is a sectional view depicting the wafer irradiated with a laserbeam;

FIG. 12B is a sectional view depicting the wafer fixed to the supportsubstrate;

FIG. 13A is a sectional view depicting the wafer irradiated with thelaser beam via a liquid column;

FIG. 13B is a sectional view depicting the wafer fixed to the supportsubstrate;

FIG. 14A is a sectional view depicting the wafer on which a mask layeris formed;

FIG. 14B is a sectional view depicting the wafer subjected to plasmaetching;

FIG. 14C is a sectional view depicting the wafer after the plasmaetching;

FIG. 15A is a perspective view depicting a wafer for preparing a devicechip;

FIG. 15B is a perspective view depicting the wafer divided into aplurality of device chips;

FIG. 16 is a perspective view depicting the wafer in a fitting step;

FIG. 17A is a sectional view depicting the wafer in which the devicechip is fitted;

FIG. 17B is a plan view depicting a through hole;

FIG. 18A is a sectional view depicting the wafer when the adhesive layeris subjected to plasma etching;

FIG. 18B is a sectional view depicting the wafer in a state in which apart of the adhesive layer is removed;

FIG. 18C is a sectional view depicting the wafer in which the devicechip having an adhesive layer adhering thereto is fitted;

FIG. 19A is a sectional view depicting the wafer in a resin fillingstep;

FIG. 19B is a sectional view depicting the wafer in a resin grindingstep;

FIG. 20 is a sectional view depicting a laminated wafer;

FIG. 21A is a sectional view depicting the laminated wafer in a dividingstep;

FIG. 21B is a sectional view depicting the laminated wafer divided intoa plurality of laminated device chips;

FIG. 22A is a sectional view depicting the wafer in which a groove isformed by sandblast processing;

FIG. 22B is a sectional view depicting the wafer in which a groove isformed by water jet processing;

FIG. 22C is a sectional view depicting the wafer in which a groove isformed by drill processing;

FIG. 23A is a sectional view depicting the wafer fixed to the supportsubstrate;

FIG. 23B is a sectional view depicting the wafer after being ground;

FIG. 24A is a sectional view depicting the wafer in which a through holeis formed by the sandblast processing;

FIG. 24B is a sectional view depicting the wafer in which a through holeis formed by the water jet processing;

FIG. 24C is a sectional view depicting the wafer in which a through holeis formed by the drill processing;

FIG. 25 is a sectional view depicting the wafer fixed to the supportsubstrate;

FIG. 26 is a sectional view depicting the wafer subjected to plasmaetching;

FIG. 27A is a plan view depicting a region processed by the sandblastprocessing or the water jet processing;

FIG. 27B is a plan view depicting regions processed by the drillprocessing;

FIG. 28A is a sectional view depicting the wafer irradiated with a laserbeam;

FIG. 28B is a sectional view depicting the wafer in which a groove isformed;

FIG. 29 is a plan view depicting paths along which the laser beam isscanned;

FIG. 30A is a sectional view depicting the wafer fixed to the supportsubstrate;

FIG. 30B is a sectional view depicting the wafer after being ground;

FIG. 31A is a sectional view depicting the wafer irradiated with thelaser beam;

FIG. 31B is a sectional view depicting the wafer fixed to the supportsubstrate;

FIG. 32 is a sectional view depicting the wafer held by a holding table;

FIG. 33A is a sectional view depicting the wafer from which thedefective device region is removed by the sandblast processing;

FIG. 33B is a sectional view depicting the wafer from which thedefective device region is removed by the water jet processing;

FIG. 33C is a sectional view depicting the wafer from which thedefective device region is removed by the drill processing;

FIG. 34A is a sectional view depicting the wafer fixed to the supportsubstrate;

FIG. 34B is a sectional view depicting the wafer after being ground;

FIG. 35A is a sectional view depicting the wafer in which a through holeis formed by the sandblast processing;

FIG. 35B is a sectional view depicting the wafer in which a through holeis formed by the water jet processing;

FIG. 35C is a sectional view depicting the wafer in which a through holeis formed by the drill processing;

FIG. 36 is a sectional view depicting the wafer fixed to the supportsubstrate;

FIG. 37A is a plan view depicting a region processed by the sandblastprocessing or the water jet processing; and

FIG. 37B is a plan view depicting regions processed by the drillprocessing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

An embodiment of the present invention will hereinafter be describedwith reference to the accompanying drawings. An example of configurationof a wafer that can be used in the present embodiment will first bedescribed. FIG. 1A is a perspective view depicting a wafer 11. FIG. 1Bis a sectional view depicting the wafer 11.

The wafer 11 is, for example, a silicon wafer formed in a disk shape.The wafer 11 has a top surface (first surface) 11 a and an undersurface(second surface) 11 b on an opposite side of the top surface 11 a. Thetop surface 11 a and the undersurface 11 b are formed substantially inparallel with each other.

The wafer 11 is demarcated into a plurality of rectangular regions by aplurality of streets (planned dividing lines) 13 arranged in a latticemanner so as to intersect each other. Then, a semiconductor device 15such as an integrated circuit (IC), large scale integration (LSI), alight emitting diode (LED), or microelectromechanical systems (MEMS) isformed in each of the plurality of regions demarcated by the streets 13on the top surface 11 a side of the wafer 11.

It is to be noted that there is no limitation on the material, shape,structure, size, or the like of the wafer 11. For example, the wafer 11may be a wafer formed of a semiconductor other than silicon (GaAs, InP,GaN, SiC, or the like), glass, ceramic, a resin, a metal, or the like.In addition, there is no limitation on the kind, quantity, shape,structure, size, arrangement, or the like of the semiconductor devices15 either.

FIG. 1C is a perspective view depicting the semiconductor device 15. Thesemiconductor device 15, for example, includes a plurality of electrodes17 that are exposed on the top surface of the semiconductor device 15and that are connected to another piece of wiring, other electrodes,another semiconductor device, or the like. Incidentally, a connectingelectrode such as a bump may be formed on each of the top surfaces ofthe electrodes 17.

In addition, a plurality of electrodes (via electrodes or throughelectrodes) 19 are embedded in each of the plurality of regionsdemarcated by the streets 13 of the wafer 11. The electrodes 19 are eachformed in a columnar shape along the thickness direction of the wafer11, and are connected to the electrodes 17 of the semiconductor device15. It is to be noted that the material of the electrodes 19 are notlimited. For example, a metal such as copper, tungsten, or aluminum isused as the material of the electrodes 19.

The electrodes 19 are each formed extending from the semiconductordevice 15 toward the undersurface 11 b side of the wafer 11. The length(height) of each of the electrodes 19 is less than the thickness of thewafer 11. Therefore, the electrodes 19 are not exposed on theundersurface 11 b side of the wafer 11, and are embedded in the wafer11. In addition, an insulating layer (not depicted) that insulates thewafer 11 from the electrodes 19 is provided between the wafer 11 and theelectrodes 19.

When the wafer 11 is thinned by subjecting the undersurface 11 b side ofthe wafer 11 to grinding processing, etching processing, or the like,the electrodes 19 are exposed on the undersurface 11 b side of the wafer11. Then, when a plurality of wafers 11 in a state in which theelectrodes 19 are exposed on the undersurface 11 b side are laminated, alaminated wafer which includes a plurality of semiconductor devices 15laminated so as to be stacked on each other is obtained. The stackedsemiconductor devices 15 are connected to each other via the electrodes19.

The laminated wafer is divided along the streets 13 by cuttingprocessing, laser processing, or the like. As a result, device chipseach including a plurality of laminated semiconductor devices 15(laminated device chips) are manufactured.

Incidentally, the wafer 11 may include a defective product of asemiconductor device 15 (defective device). FIG. 1A and FIG. 1B depictan example in which the wafer 11 includes a defective device 15 a. Thedefective device 15 a, for example, corresponds to a semiconductordevice 15 not meeting a standard of predetermined electricalcharacteristics determined in advance.

When the laminated wafer is formed by laminating the wafer 11 includingthe defective device 15 a, and the laminated wafer is divided, alaminated device chip including the defective device 15 a ismanufactured. Then, when some of the semiconductor devices 15 includedin the laminated device chip are the defective devices 15 a, thelaminated device chip as a whole is determined to be a defective product(defective chip) even if the other semiconductor devices 15 arenon-defective products.

Accordingly, a wafer manufacturing method according to the presentembodiment removes the defective device 15 a from the wafer 11. Then, asemiconductor device 15 as a non-defective product is fitted into aremoved region (gap) formed in the wafer 11 by removing the defectivedevice 15 a. The wafer 11 not including the defective device 15 a isthereby manufactured. A concrete example of the wafer manufacturingmethod according to the present embodiment will be described in thefollowing.

First, the wafer 11 which has the semiconductor device 15 formed in eachof the plurality of regions demarcated by the plurality of streets 13intersecting each other (see FIG. 1A and FIG. 1B) is prepared (waferpreparing step). Incidentally, because a laminated wafer is formed bylaminating a plurality of wafers in a subsequent step, at least two ormore wafers are preferably prepared in the wafer preparing step.

Next, the wafer 11 is ground and thinned (grinding step). A grindingapparatus, for example, is used to grind the wafer 11. FIG. 2 is a frontview depicting a grinding apparatus 2. The grinding apparatus 2 includesa chuck table 4 that holds the wafer 11 and a grinding unit 6 thatgrinds the wafer 11.

The upper surface of the chuck table 4 constitutes a flat holdingsurface 4 a that holds the wafer 11. The holding surface 4 a isconnected to a suction source (not depicted) such as an ejector via aflow passage (not depicted) formed within the chuck table 4. Inaddition, the chuck table 4 is coupled with a moving mechanism (notdepicted) that moves the chuck table 4 along a horizontal direction.Used as the moving mechanism is a moving mechanism of a ball screw type,a turn table that supports and rotates the chuck table 4, or the like.Further, the chuck table 4 is coupled with a rotational driving source(not depicted) such as a motor that rotates the chuck table 4 about arotational axis substantially parallel with a vertical direction(upward-downward direction).

The grinding unit 6 is disposed above the chuck table 4. The grindingunit 6 includes a cylindrical spindle 8 disposed along the verticaldirection. A disk-shaped mount 10 formed of a metal or the like is fixedto a distal end portion (lower end portion) of the spindle 8. Inaddition, a rotational driving source (not depicted) such as a motorthat rotates the spindle 8 is connected to a proximal end portion (upperend portion) of the spindle 8.

A grinding wheel 12 that grinds the wafer 11 is fitted to the lowersurface side of the mount 10. The grinding wheel 12 includes an annularbase 14 formed of a metal such as stainless steel or aluminum and formedwith substantially a same diameter as that of the mount 10. A pluralityof grinding stones 16 are fixed to the lower surface side of the base14. For example, the plurality of grinding stones 16 are formed in arectangular parallelepipedic shape, and are arranged at substantiallyequal intervals along the outer circumference of the base 14.

Power transmitted from the rotational driving source to the grindingwheel 12 via the spindle 8 and the mount 10 rotates the grinding wheel12 about a rotational axis substantially parallel with the verticaldirection. In addition, a ball screw type moving mechanism (notdepicted) that raises and lowers the grinding unit 6 along the verticaldirection is coupled to the grinding unit 6. Further, a nozzle 18 thatsupplies a grinding liquid 20 such as pure water to the wafer 11 held bythe chuck table 4 and the plurality of grinding stones 16 is provided inthe vicinity of the grinding unit 6.

The grinding apparatus 2 grinds, for example, the undersurface 11 b sideof the wafer 11. In this case, first, a protective member 21 is affixedto the top surface 11 a side of the wafer 11 on which surface side thesemiconductor devices 15 are formed. The semiconductor devices 15 arethereby covered and protected by the protective member 21.

Usable as the protective member 21 is a circular tape (protective tape)including a film-shaped base material and an adhesive layer (glue layer)on the base material or the like. For example, the base material isformed of a resin such as polyolefin, polyvinyl chloride, orpolyethylene terephthalate, and the adhesive layer is formed of anepoxy-based, an acryl-based, or a rubber-based adhesive. In addition, anultraviolet curable resin cured by being irradiated with ultravioletrays may be used as the adhesive layer.

Then, the wafer 11 is held by the chuck table 4. Specifically, the wafer11 is disposed on the chuck table 4 such that the top surface 11 a side(protective member 21 side) of the wafer 11 faces the holding surface 4a and the undersurface 11 b side of the wafer 11 is exposed upward. Whena negative pressure of the suction source is made to act on the holdingsurface 4 a in this state, the top surface 11 a side of the wafer 11 issucked and held by the chuck table 4 via the protective member 21.

Next, the chuck table 4 is moved to a position below the grinding unit6. Then, while the chuck table 4 and the grinding wheel 12 are eachrotated in a predetermined direction at a predetermined rotationalspeed, the grinding wheel 12 is lowered to the chuck table 4. Thelowering speed of the grinding wheel 12 at this time is adjusted suchthat the grinding stones 16 are pressed against the wafer 11 with anappropriate force.

When the grinding stones 16 come into contact with the undersurface 11 bside of the wafer 11, the undersurface 11 b side of the wafer 11 isscraped away. Consequently, the undersurface 11 b side of the wafer 11is ground, and the wafer 11 is thinned. Then, when the wafer 11 isthinned to a predetermined thickness, the grinding is stopped. Theprotective member 21 is thereafter peeled and removed from the wafer 11.

Incidentally, before or after the grinding step, an inspection thatdetermines whether the semiconductor devices 15 are a non-defectiveproduct or a defective product is performed for each of thesemiconductor devices 15 included in the wafer 11. In the inspection ofthe semiconductor device 15, for example, electrical characteristics ofthe semiconductor device 15 are measured by applying a metallic probe tothe electrodes 17 exposed on the top surface of the semiconductor device15 (probing). Then, whether the semiconductor device 15 is anon-defective product or a defective product is determined on the basisof whether or not the measured electrical characteristics satisfy apredetermined standard.

When the wafer 11 includes a defective product of a semiconductor device15 (defective device 15 a), the semiconductor device 15 is determined tobe a defective product by the inspection. Then, the position of thesemiconductor device 15 determined to be a defective product isrecorded.

Next, a defective device region including the semiconductor device 15(defective device 15 a) determined to be a defective product among theplurality of semiconductor devices 15 formed in the wafer 11 is removedfrom the wafer 11 (removing step). FIG. 3A is a sectional view depictingthe wafer 11 in the removing step.

In the removing step, for example, a region of the wafer 11 is removedalong four streets 13 surrounding the defective device 15 a.Consequently, a defective device region 11 c in a rectangularparallelepipedic shape including the defective device 15 a is removedand separated from the wafer 11. Then, a through hole (removed region)11 d in a rectangular parallelepipedic shape extending from the topsurface 11 a to the undersurface 11 b of the wafer 11 is formed in aposition where the defective device region 11 c of the wafer 11 existed.

FIG. 3B is a perspective view depicting the wafer 11 in which thethrough hole 11 d is formed. The wafer 11 not including the defectivedevice 15 a is obtained by removing the defective device region 11 c.Incidentally, when the above-described grinding step (see FIG. 2) isperformed in advance before the removing step is performed, the wafer 11is thinned, and thus the defective device region 11 c is removed fromthe wafer 11 easily. However, when there is no difficulty in removingthe defective device region 11 c, the grinding step may be omitted.

Various methods can be used to remove the defective device region 11 c.For example, the defective device region 11 c is separated from thewafer 11 by applying a laser beam along the streets 13 surrounding thedefective device 15 a. In the following, description will be made of anexample in which the wafer 11 is subjected to laser processing in theremoving step.

FIG. 4A is a sectional view depicting the wafer 11 irradiated with alaser beam 32A. In the removing step, first, the top surface 11 a sideof the wafer 11 is fixed to a support substrate 23 that supports thewafer 11. The support substrate 23 is, for example, a plate-shapedmember formed of silicon, glass, ceramic, or the like. The top surface11 a side of the wafer 11 is fixed to the support substrate 23 via anadhesive layer 25. Consequently, the wafer 11 is supported by thesupport substrate 23 in a state in which the undersurface 11 b side isexposed.

The material of the adhesive layer 25 is not limited, and is selected asappropriate according to the materials of the wafer 11 and the supportsubstrate 23. For example, usable as the adhesive layer 25 is anadhesive formed of a thermosetting resin cured by heating, an adhesiveformed of a thermoplastic resin softened by heating, an adhesive formedof an ultraviolet curable resin cured by application of ultravioletrays, or the like.

In addition, the adhesive layer 25 may be a sheet that can be fixed tothe wafer 11 and the support substrate 23 by heating and pressurization(thermocompression bonding sheet). For example, the adhesive layer 25 isa flexible sheet formed of a thermoplastic resin having a lower meltingpoint than those of the wafer 11 and the support substrate 23, and doesnot include an adhesive (glue layer). When the wafer 11 is pressedagainst the support substrate 23 via the thermocompression bonding sheetwhile the thermocompression bonding sheet is heated, thethermocompression bonding sheet closely adheres to the wafer 11 and thesupport substrate 23. The wafer 11 is thereby fixed to the supportsubstrate 23. Concrete examples of the sheet include a polyolefin(PO)-based sheet and a polyester (PE)-based sheet.

The polyolefin-based sheet is a sheet formed of a polymer synthesizedwith alkene as a monomer. Examples of the polyolefin-based sheet includea polyethylene sheet, a polypropylene sheet, a polystyrene sheet, andthe like. In addition, a sheet formed of a copolymer of propylene andethylene and a sheet formed of an olefin-based elastomer can also beused.

The polyester-based sheet is a sheet formed of a polymer synthesizedwith a dicarboxylic acid (compound having two carboxyl groups) and adiol (compound having two hydroxyl groups) as monomers. Examples of thepolyester-based sheet include a polyethylene terephthalate sheet, apolyethylene naphthalate sheet, and the like. In addition, apolytrimethylene terephthalate sheet, a polybutylene terephthalatesheet, or a polybutylene naphthalate sheet can also be used.

Incidentally, when the wafer 11 is fixed to the support substrate 23 viathe adhesive layer 25, the wafer 11 is preferably provisionally fixed tothe support substrate 23 without the adhesive layer 25 being made toadhere firmly to the wafer 11 and the support substrate 23. This makesthe defective device region 11 c easily peeled off from the adhesivelayer 25 when the defective device region 11 c is to be separated fromthe wafer 11 in a subsequent step (see FIG. 8B).

For example, in a case where the adhesive layer 25 is an adhesive formedof a thermosetting resin, the wafer 11 is fixed to the support substrate23 by performing heating treatment at a lower temperature or for ashorter time than in a case where the thermosetting resin is completelyfixed to the wafer 11 and the support substrate 23. In addition, in acase where the adhesive layer 25 is an adhesive formed of athermoplastic resin, the wafer 11 is fixed to the support substrate 23in a state in which the thermoplastic resin is softened by heating to apredetermined temperature.

In a case where the adhesive layer 25 is an adhesive formed of anultraviolet curable resin, the wafer 11 is fixed to the supportsubstrate 23 without the ultraviolet curable resin being subjected toheating treatment. In addition, in a case where the adhesive layer 25 isa thermocompression bonding sheet, the wafer 11 is fixed to the supportsubstrate 23 by performing heating treatment at a lower temperature orfor a shorter time than in a case where the thermocompression bondingsheet is completely fixed to the wafer 11 and the support substrate 23.

In addition, in place of the support substrate 23, a tape formed of aresin or the like may be affixed to the top surface 11 a side of thewafer 11. Examples of the structure and material of the tape are similarto those of the protective member 21 (see FIG. 2).

Next, the wafer 11 is subjected to laser processing. A laser processingapparatus is used for the laser processing of the wafer 11. The laserprocessing apparatus includes a chuck table (not depicted) that holdsthe wafer 11 and a laser irradiating unit 30A that irradiates the wafer11 with the laser beam 32A. The laser irradiating unit 30A includes alaser oscillator that oscillates a laser of a predetermined wavelengthand a condenser (condensing lens) that condenses a laser beam emittedfrom the laser oscillator.

Irradiation conditions of the laser beam 32A are set such that a regionof the wafer 11 which is irradiated with the laser beam 32A is modified(altered) by multiphoton absorption. Specifically, the wavelength of thelaser beam 32A is set such that at least a part of the laser beam 32Apasses through the wafer 11. That is, the laser irradiating unit 30Aapplies the laser beam 32A having a wavelength transmissible through thewafer 11. In addition, other irradiation conditions (power, pulse width,spot diameter, repetition frequency, and the like) of the laser beam 32Aare set such that the wafer 11 is modified appropriately.

Then, the laser beam 32A is applied along the four streets 13surrounding the defective device 15 a in a state in which the condensingpoint of the laser beam 32A is positioned inside the wafer 11.Incidentally, it suffices to apply the laser beam 32A so as to surroundthe defective device 15 a, and a concrete scanning path of the laserbeam 32A is set as appropriate.

FIGS. 5A to 5C depict examples of the scanning path of the laser beam32A. FIG. 5A is a plan view depicting a path 34A in a quadrangular shapewith rounded corners. FIG. 5B is a plan view depicting a rectangularpath 34B. FIG. 5C is a plan view depicting a plurality of linear paths34C. Each of the path 34A, the path 34B, and the plurality of paths 34Cis set so as to be superposed on the street 13.

For example, the laser beam 32A is scanned so as to surround thedefective device 15 a along the path 34A in a substantially rectangularshape having four corners formed in the shape of an arc. In addition,the laser beam 32A may be scanned along the path 34B in a rectangularshape surrounding the defective device 15 a. Incidentally, in the casewhere the laser beam 32A is scanned along the path 34A or the path 34B,the laser beam 32A is continuously applied to the wafer 11 so as tosurround the defective device 15 a (drawing with one stroke).

In addition, the laser beam 32A may be scanned along the four linearpaths 34C along the four streets 13 surrounding the defective device 15a. Incidentally, the paths 34C are not coupled to each other, so thatthe laser beam 32A is applied intermittently so as to surround thedefective device 15 a.

FIG. 4B is a sectional view depicting the wafer 11 in which a modifiedlayer (altered layer) 27 is formed. When the laser beam 32A is appliedalong the streets 13 surrounding the defective device 15 a, the wafer 11is modified by multiphoton absorption, and the modified layer 27 isformed in the wafer 11 along the streets 13. Then, a region in which themodified layer 27 is formed is fragile than other regions of the wafer11. Therefore, when an external force is applied to the wafer 11, forexample, the wafer 11 ruptures along the modified layer 27. That is, themodified layer 27 functions as a starting point (trigger) of separationof the defective device region 11 c.

It has been confirmed that the application of the laser beam 32A alongthe path 34A depicted in FIG. 5A or the paths 34C depicted in FIG. 5C,in particular, effectively suppresses the occurrence of unintendedirregular cracks at four corners (corner portions) of the path 34A or34C. In this case, the modified layer 27 formed at the four corners ofthe path 34A or 34C properly functions as a starting point of division,and the defective device region 11 c is correctly separated easily.

Incidentally, the modified layer 27 may be formed by applying the laserbeam 32A along each street 13 a plurality of times while the heightposition of the condensing point of the laser beam 32A is changed. Inthis case, the modified layer 27 is formed by modified regions formed ina plurality of stages along the thickness direction of the wafer 11.

FIG. 4C is a sectional view depicting a modified layer 27 including aplurality of modified regions (altered regions) 27 a. For example, themodified regions 27 a in a plurality of stages are formed in the wafer11 along each street 13 at different depth positions in the thicknessdirection of the wafer 11.

Incidentally, the plurality of modified regions 27 a may be formed so asnot to overlap each other as viewed in plan. Specifically, as depictedin FIG. 4C, the plurality of modified regions 27 a are formed such thatthe closer to the undersurface 11 b side of the wafer 11 a modifiedregion 27 a is formed, the more distant from the defective device 15 athe position of the modified region 27 a is in the horizontal direction(direction perpendicular to the thickness direction of the wafer 11). Inthis case, the modified layer 27 inclined with respect to the thicknessdirection of the wafer 11 is formed (see FIG. 4B), so that it becomeseasy to separate the defective device region 11 c from the wafer 11 in asubsequent step (see FIG. 8B). However, there is no limitation on theshape of the modified layer 27. The modified layer 27 may be formed inparallel with the thickness direction of the wafer 11.

Next, a processed region (modified layer 27) processed by theapplication of the laser beam 32A or a crack developed from theprocessed region (modified layer 27) is exposed on the undersurface 11 bside of the wafer 11 by grinding the undersurface 11 b side of the wafer11. The grinding apparatus 2 depicted in FIG. 2, for example, is used togrind the wafer 11.

The undersurface 11 b side of the wafer 11 is ground by bringing thegrinding stones 16 into contact with the undersurface 11 b side of thewafer 11 held by the chuck table 4. Then, for example, the wafer 11 isground and thinned until the modified layer 27 is exposed on theundersurface 11 b side of the wafer 11.

FIG. 6 is a sectional view depicting the wafer 11 after being ground.When the wafer 11 is ground by pressing the grinding stones 16 (see FIG.2) against the wafer 11, an external force (pressure) is applied to thewafer 11, and the wafer 11 ruptures along the modified layer 27. Inaddition, a crack 29 occurring in the modified layer 27 develops, andreaches the top surface 11 a of the wafer 11. As a result, the defectivedevice region 11 c is divided from the wafer 11.

Incidentally, the crack 29 developed from the modified layer 27 to thetop surface 11 a of the wafer 11 may occur when the modified layer 27 isformed by applying the laser beam 32A (see FIG. 4A and FIG. 4B).Specifically, appropriate setting of the irradiation conditions of thelaser beam 32A and the position at which the modified layer 27 is formedcan make the crack 29 occurring at the same time as the formation of themodified layer 27 reach the top surface 11 a of the wafer 11.

In addition, after the grinding of the wafer 11, the wafer 11 ispreferably subjected to etching processing. For example, the wafer 11 issubjected to plasma etching. A plasma processing apparatus is used forthe plasma etching. The plasma processing apparatus includes a chucktable having a holding surface for holding the wafer 11 and a chamber(processing chamber) housing the chuck table.

FIG. 7A is a sectional view depicting the wafer 11 subjected to theplasma etching. When the plasma etching is performed, the chamber issealed in a state in which the wafer 11 is held by the chuck table, andthe inside of the chamber is supplied with gas (etching gas) 36 for theetching. Then, the plasma processing apparatus sets gas 36 within thechamber in a plasma state including ions and radicals by a highfrequency voltage. Consequently, the gas 36 converted into plasma issupplied to the wafer 11.

In a case where the wafer 11 is a silicon wafer, for example,fluorine-based gas such as CF4 or SF6 is used as the gas 36. However,the component of the gas 36 is selected as appropriate according to thematerial of the wafer 11. Then, the gas 36 in the plasma state acts onthe wafer 11, and thus the wafer 11 is subjected to the plasma etching.

FIG. 7B is a sectional view depicting the wafer 11 after the plasmaetching. When the gas 36 converted into plasma is supplied to theundersurface 11 b side of the wafer 11, the gas 36 enters the modifiedlayer 27 and the crack 29, and the insides of the modified layer 27 andthe crack 29 are etched. As a result, a gap between the wafer 11 and thedefective device region 11 c is expanded, and the defective deviceregion 11 c is surely divided from the wafer 11.

However, the gas 36 may be supplied to the inside of the chamber via asupply pipe made of a metal after the gas 36 is converted into plasmaoutside the chamber. In this case, when the gas 36 converted into plasmapasses through the supply pipe, ions included in the gas are adsorbed bythe inner wall of the supply pipe, and do not easily reach the inside ofthe chamber. As a result, the gas 36 having a high radical ratio isintroduced into the chamber, and is supplied to the wafer 11. The gas 36having a high radical ratio easily enters narrow regions in the wafer11. Thus, the gas 36 easily etches the insides of the modified layer 27and the crack 29.

In addition, the kind of etching processing is not limited to the plasmaetching. For example, the wafer 11 may be subjected to wet etching bysupplying an etchant to the undersurface 11 b side of the wafer 11.Specifically, in a case where the wafer 11 is a silicon wafer, anetchant including potassium hydroxide (KOH), tetramethylammoniumhydroxide (TMAH), or the like is supplied to the wafer 11. Then, theetchant enters the modified layer 27 and the crack 29. The insides ofthe modified layer 27 and the crack 29 are thereby etched, so that themodified layer 27 and the crack 29 are expanded.

Incidentally, in a case where the modified layer 27 formed by theapplication of the laser beam 32A (see FIG. 4B) is located more on theundersurface 11 b side of the wafer 11 than the electrode 19, the wafer11 is preferably ground and thinned until all of the modified layer 27is removed. In this case, the wafer 11 that does not include themodified layer 27 but in which only the crack 29 developed from themodified layer 27 remains is obtained. When the modified layer 27 isthus removed from the wafer 11 in advance, a decrease in transverserupture strength (bending strength) of device chips ultimately obtainedby dividing the wafer 11 is prevented.

In the case where the modified layer 27 is removed from the wafer 11 asdescribed above, the crack 29 is exposed on the undersurface 11 b sideof the wafer 11 by grinding, and the defective device region 11 c isthus divided from the wafer 11. Then, the gas 36 converted into plasmaor an etchant is supplied to the inside of the crack 29, so that thecrack 29 is expanded.

In addition, when the modified layer 27 is formed by the application ofthe laser beam 32A (see FIG. 4A and FIG. 4B), or when the undersurface11 b side of the wafer 11 is ground (see FIG. 6), a crack developed fromthe modified layer 27 toward the undersurface 11 b side of the wafer 11may occur. In this case, when the crack is exposed on the undersurface11 b of the wafer 11 by the grinding of the wafer 11, the defectivedevice region 11 c is divided from the wafer 11.

Next, the defective device region 11 c is removed from the wafer 11.Specifically, the defective device region 11 c is separated from thewafer 11 by peeling and picking up the defective device region 11 c fromthe adhesive layer 25.

When the defective device region 11 c is to be separated from the wafer11, processing (preprocessing) of partly reducing the adhesive power ofthe adhesive layer 25 is preferably performed first. For example, thesupply of a chemical solution to the adhesive layer 25 via the modifiedlayer 27 and the crack 29 partly reduces the adhesive power of theadhesive layer 25, or partly removes the adhesive layer 25.

In addition, in a case where the adhesive layer 25 is formed of amaterial whose adhesive power is reduced by application of predeterminedenergy (heating, application of an electromagnetic wave, or the like),the adhesive power of the adhesive layer 25 may be reduced by applyingenergy to the adhesive layer 25. For example, in a case where theadhesive layer 25 is an adhesive formed of a thermoplastic resin, theadhesive power of the adhesive layer 25 can be reduced by heating theadhesive layer 25. In addition, in a case where the adhesive layer 25 isan adhesive formed of an ultraviolet curable resin, the adhesive powerof the adhesive layer 25 can be reduced by applying ultraviolet rays tothe adhesive layer 25.

In addition, as the adhesive layer 25, a tape which includes afilm-shaped base material, a thermally foamed layer provided on onesurface side of the base material, and an adhesive layer provided onanother surface side of the base material can also be used. Thethermally foamed layer of this tape is formed by including an expandingmaterial expanded by heating in an adhesive.

Usable as the adhesive of the thermally foamed layer is an acryl-basedadhesive, a rubber-based adhesive, a vinyl alkyl ether-based adhesive, asilicone-based adhesive, a polyester-based adhesive, a polyamide-basedadhesive, a urethane-based adhesive, or the like. In addition, usable asthe expanding material of the thermally foamed layer is microspheresexpanded by heating (thermally expandable microspheres), a foamedmaterial foamed by heating, or the like.

The thermally expandable microspheres are formed by including a materialexpanded by heating in microcapsules having elasticity. Usable as thematerial expanded by heating is, for example, propane, propylene,butene, or the like. An example of a commercially available product of atape including the thermally expandable microspheres is REVALPHA(registered trademark) manufactured by Nitto Denko Corporation. Inaddition, usable as the foamed material foamed by heating are, forexample, inorganic-based foam agents such as ammonium carbonate,ammonium hydrogen carbonate, sodium hydrogen carbonate, ammoniumnitrite, sodium borohydride, and azides and various kinds oforganic-based foam agents.

The above-described tape is affixed to the wafer 11 and the supportsubstrate 23 such that the thermally foamed layer side is in contactwith the wafer 11 and the adhesive layer side is in contact with thesupport substrate 23. Then, when the tape is heated, the expandingmaterial included in the thermally foamed layer expands in a heatedregion of the tape, and forms projections and depressions, so that theadhesive power of the tape adhering to the wafer 11 is decreased.

FIG. 8A is a sectional view depicting the wafer 11 when preprocessing isperformed on the adhesive layer 25. For example, a mask 38 is fixed to asurface (lower surface) side of the support substrate 23 which surfaceside is on an opposite side of a surface (upper surface) of the supportsubstrate 23 to which surface the wafer 11 is fixed. Incidentally, themask 38 has an opening 38 a vertically penetrating the mask 38, and isfixed such that the opening 38 a coincides with the defective deviceregion 11 c.

In addition, an energy applying unit 40 that applies energy to theadhesive layer 25 is disposed below the support substrate 23. The energyapplying unit 40 applies energy to the adhesive layer 25 via the opening38 a of the mask 38. Incidentally, the kind of the energy applied fromthe energy applying unit 40 to the adhesive layer 25 is selectedaccording to the properties of the adhesive layer 25.

For example, in a case where the adhesive layer 25 is an adhesive formedof a thermoplastic resin or a tape including a thermally foamed layer, aheater is used as the energy applying unit 40. In addition, a heatinsulating member is used as the mask 38. Then, heat is applied from theenergy applying unit 40 to a region coinciding with the opening 38 a ofthe mask 38 in the support substrate 23, and the heat of the supportsubstrate 23 is transmitted to the adhesive layer 25. Consequently, aregion coinciding with the opening 38 a of the mask 38 in the adhesivelayer 25 is partly heated.

In addition, in a case where the adhesive layer 25 is an adhesive formedof an ultraviolet curable resin, a light source (lamp) that appliesultraviolet rays is used as the energy applying unit 40. In addition, amember having a transmitting property for ultraviolet rays is used asthe support substrate 23, and a member having a light shielding propertyfor ultraviolet rays is used as the mask 38. Then, ultraviolet rays areapplied from the energy applying unit 40 to the adhesive layer 25 viathe opening 38 a of the mask 38 and the support substrate 23.Consequently, the region coinciding with the opening 38 a of the mask 38in the adhesive layer 25 is partly irradiated with the ultraviolet rays.

When energy is applied from the energy applying unit 40 to the adhesivelayer 25, the adhesive power of a region coinciding with the defectivedevice region 11 c in the adhesive layer 25 is partly decreased.Consequently, the defective device region 11 c is easily peeled off fromthe adhesive layer 25.

FIG. 8B is a sectional view depicting the wafer 11 when the defectivedevice region 11 c is separated. After preprocessing is performed on thewafer 11 as required, the defective device region 11 c is held andseparated from the wafer 11. Consequently, the defective device region11 c is peeled off from the adhesive layer 25, and is removed from thewafer 11.

Incidentally, when the defective device region 11 c is separated fromthe wafer 11, the irradiation of the wafer 11 or the support substrate23 with an ultrasonic wave may assist in separating the defective deviceregion 11 c. FIG. 9 is a sectional view depicting an ultrasonicirradiating unit 42.

The ultrasonic irradiating unit 42 has a box-shaped container 44 formedin a rectangular parallelepipedic shape. A liquid 46 such as pure wateris retained within the container 44. In addition, an ultrasonictransmitter 48 that emits an ultrasonic wave is provided within thecontainer 44.

The wafer 11 in which the modified layer 27 and the crack 29 are formedis housed in the container 44 so as to be immersed in the liquid 46. Atthis time, the wafer 11 is, for example, disposed such that the supportsubstrate 23 faces the ultrasonic transmitter 48. When the ultrasonictransmitter 48 is made to transmit an ultrasonic wave in this state, theultrasonic wave propagates with the liquid 46 as a medium, and reachesthe support substrate 23, so that an ultrasonic vibration is applied tothe support substrate 23.

Even if the wafer 11 is in a state of not rupturing sufficiently alongthe modified layer 27 and the crack 29, the vibration of the supportsubstrate 23 promotes the rupture of the wafer 11 when the ultrasonicvibration is applied to the support substrate 23. In addition, thevibration of the support substrate 23 weakens bonding between thedefective device region 11 c and the adhesive layer 25. As a result, thedefective device region 11 c is separated from the wafer 11 easily.Incidentally, the ultrasonic wave may be partly applied to the regioncoinciding with the defective device region 11 c in the supportsubstrate 23.

The defective device region 11 c is thus separated from the wafer 11.Then, the through hole 11 d penetrating the wafer 11 in the thicknessdirection is formed in a position where the defective device region 11 cof the wafer 11 existed (see FIG. 8B).

Incidentally, in the above description, a method of rupturing the wafer11 along the modified layer 27 and the crack 29 formed by theapplication of the laser beam 32A has been described as an example.However, the content of the laser processing performed on the wafer 11is not limited to the formation of the modified layer 27 and the crack29. For example, in the removing step, it is also possible to separatethe defective device region 11 c from the wafer 11 by performingablation processing on the wafer 11.

FIG. 10A is a sectional view depicting the wafer 11 irradiated with alaser beam 32B. In a case where the ablation processing is performed onthe wafer 11, a laser irradiating unit 30B which irradiates the wafer 11with the laser beam 32B is used. Incidentally, the configuration of thelaser irradiating unit 30B is similar to that of the laser irradiatingunit 30A (see FIG. 4A).

However, irradiation conditions of the laser beam 32B are set such thata region of the wafer 11 which is irradiated with the laser beam 32B isremoved by the ablation processing. Specifically, the wavelength of thelaser beam 32B is set such that at least a part of the laser beam 32B isabsorbed by the wafer 11. That is, the laser irradiating unit 30Bapplies the laser beam 32B of a wavelength absorbable by the wafer 11.In addition, other irradiation conditions of the laser beam 32B are alsoset such that the ablation processing is properly performed on the wafer11.

The laser beam 32B is, for example, applied to the top surface 11 a sideof the wafer 11. Specifically, the wafer 11 is held by the chuck table(not depicted) of the laser processing apparatus such that the topsurface 11 a side is exposed. Then, in a state in which the condensingpoint of the laser beam 32B is positioned at a street 13 of the wafer11, the laser beam 32B is applied along the four streets 13 surroundingthe defective device 15 a. It is to be noted that the scanning path ofthe laser beam 32B is not limited. For example, the laser beam 32B isscanned along the path 34A or the path 34B depicted in FIG. 5A or FIG.5B.

FIG. 10B is a sectional view depicting the wafer 11 in which a groove 31is formed. When the laser beam 32B is applied along the four streets 13surrounding the defective device 15 a, a region along the streets 13 onthe top surface 11 a side of the wafer 11 is removed by the ablationprocessing. As a result, on the top surface 11 a side of the wafer 11,the groove 31 in a rectangular shape as viewed in plan is formed alongthe streets 13.

It is to be noted that the shape of the groove 31 is not limited. Forexample, the groove 31 may be formed so as to have a width fixed in thethickness direction of the wafer 11, or may be formed so as to have awidth increasing toward the undersurface 11 b side of the wafer 11, asdepicted in FIG. 10B.

In addition, when the groove 31 is formed, the top surface 11 a side ofthe wafer 11 may be covered by a protective film, and the wafer 11 maybe irradiated with the laser beam 32B via the protective film. Usable asthe protective film is, for example, a tape made of a resin or a filmformed of a water-soluble resin such as polyvinyl alcohol (PVA) orpolyethylene glycol (PEG). When the protective film is formed on the topsurface 11 a side of the wafer 11, a processing waste (debris) producedat the time of the ablation processing can be prevented from adhering tothe top surface 11 a of the wafer 11, so that contamination of the wafer11 and the semiconductor devices 15 is avoided.

In addition, the wafer 11 may be subjected to etching processing bysupplying gas converted into plasma or an etchant to the processedregion (groove 31) processed by the application of the laser beam 32B.Consequently, the groove 31 is expanded, and minute projections anddepressions formed on the inner wall of the groove 31 by the ablationprocessing are removed.

When the wafer 11 is to be subjected to the etching processing, a maskcovering the top surface 11 a side of the wafer 11 is preferably formed.This mask is provided with an opening for exposing the region where thegroove 31 is formed in the wafer 11. Then, the gas converted into plasmaor the etchant is supplied to the wafer 11 via the mask. Thus, thesemiconductor devices 15 formed on the top surface 11 a side of thewafer 11 are protected.

It is to be noted that there is no limitation on the material of themask used in the etching processing. For example, a resist formed of aphotosensitive resin is used as the mask. Also usable as the mask is theabove-described protective film (PVA, PEG, or the like) formed on thetop surface 11 a side of the wafer 11 at the time of the application ofthe laser beam 32B.

Next, the processed region (groove 31) processed by the application ofthe laser beam 32B is exposed on the undersurface 11 b side of the wafer11 by grinding the undersurface 11 b side of the wafer 11. When thewafer 11 is to be ground, first, the wafer 11 is fixed to the supportsubstrate. FIG. 11A is a sectional view depicting the wafer 11 fixed tothe support substrate 23. In a case where the undersurface 11 b side ofthe wafer 11 is ground, the top surface 11 a side of the wafer 11 isfixed to the support substrate 23 via the adhesive layer 25.

Next, the grinding apparatus 2 (see FIG. 2) grinds the wafer 11.Specifically, the undersurface 11 b side of the wafer 11 is ground bybringing the grinding stones 16 into contact with the undersurface 11 bside of the wafer 11. Then, the wafer 11 is ground and thinned until thegroove 31 is exposed on the undersurface 11 b side of the wafer 11.

FIG. 11B is a sectional view depicting the wafer 11 after being ground.When the groove 31 is exposed on the undersurface 11 b side of the wafer11, the defective device region 11 c is divided from the wafer 11.Thereafter, as described earlier, the defective device region 11 c isseparated from the wafer 11, and the through hole 11 d is formed in thewafer 11 (see FIG. 8A, FIG. 8B, and FIG. 9).

In addition, in the removing step, the wafer 11 may be cut by applying alaser beam. Specifically, a kerf (slit) extending from the top surface11 a to the undersurface 11 b of the wafer 11 is formed along thestreets 13 by ablation processing.

FIG. 12A is a sectional view depicting the wafer 11 irradiated with alaser beam 32C. A laser irradiating unit 30C that irradiates the wafer11 with the laser beam 32C is used to cut the wafer 11. Incidentally,the configuration of the laser irradiating unit 30C is similar to thatof the laser irradiating unit 30A (see FIG. 4A).

However, irradiation conditions of the laser beam 32C are set such thata region extending from the top surface 11 a to the undersurface 11 b ofthe wafer 11 is removed by the ablation processing. Specifically, thewavelength of the laser beam 32C is set such that at least a part of thelaser beam 32C is absorbed by the wafer 11. That is, the laserirradiating unit 30C applies the laser beam 32C of a wavelengthabsorbable by the wafer 11. In addition, other irradiation conditions ofthe laser beam 32C are also set such that the region extending from thetop surface 11 a to the undersurface 11 b of the wafer 11 is removed.

When the wafer 11 is to be irradiated with the laser beam 32C, first, aprotective member 33 such as a tape is affixed to the wafer 11. Forexample, in a case where the top surface 11 a side of the wafer 11 isirradiated with the laser beam 32C, a tape is affixed as the protectivemember 33 to the undersurface 11 b side of the wafer 11.

Next, the laser beam 32C is applied to the top surface 11 a side of thewafer 11. Specifically, in a state in which the condensing point of thelaser beam 32C is positioned at a street 13 of the wafer 11, the laserbeam 32C is applied along the four streets 13 surrounding the defectivedevice 15 a. It is to be noted that the scanning path of the laser beam32C is not limited. For example, the laser beam 32C is scanned along thepath 34A or the path 34B depicted in FIG. 5A or FIG. 5B.

When the laser beam 32C is applied along the streets 13 surrounding thedefective device 15 a, a region of the wafer 11 is removed along thestreets 13. As a result, in the wafer 11, a kerf (slit) 35 extendingfrom the top surface 11 a to the undersurface 11 b is formed along thestreets 13. As a result, the defective device region 11 c is dividedfrom the wafer 11.

Incidentally, in a case where it is difficult to form the kerf 35reaching the undersurface 11 b of the wafer 11 by merely scanning thelaser beam 32C along the streets 13 once, the laser beam 32C may bescanned along each street 13 a plurality of times. Thereafter, asdescribed earlier, the defective device region 11 c is separated fromthe wafer 11, and the through hole 11 d is formed in the wafer 11 (seeFIG. 8A, FIG. 8B, and FIG. 9).

After the defective device region 11 c is separated from the wafer 11,the wafer 11 is fixed to the support substrate 23. FIG. 12B is asectional view depicting the wafer 11 fixed to the support substrate 23.After the kerf 35 is formed in the wafer 11 and the defective deviceregion 11 c is separated, the support substrate 23 is fixed to the topsurface 11 a side of the wafer 11 via the adhesive layer 25. Theprotective member 33 is thereafter peeled and removed from theundersurface 11 b side of the wafer 11.

In addition, in the removing step, it is also possible to process thewafer 11 by a laser beam applied via a liquid (aqua laser). FIG. 13A isa sectional view depicting the wafer 11 irradiated with the laser beam32C via a liquid column 50.

The laser irradiating unit 30C may include a jetting unit (nozzle) thatjets a liquid to the wafer 11. In this case, the liquid column 50extending from the laser irradiating unit 30C to the wafer 11 is formedby continuously supplying the liquid from the jetting unit to the wafer11. The liquid column 50 is a column formed by a flowing liquid. Theliquid column 50 functions as a light guiding path for propagating thelaser beam 32C. For example, water is jetted from the jetting unit, anda water column is formed.

The wafer 11 is held by a holding table 52. The upper surface of theholding table 52 constitutes a flat holding surface 52 a that holds thewafer 11. In addition, the holding table 52 is provided with an opening52 b that vertically penetrates the holding table 52. The opening 52 bis formed in a rectangular shape as viewed in plan so as to correspondto the four streets 13 surrounding the semiconductor device 15. Thewafer 11 is disposed on the holding table 52 such that each of the fourstreets 13 surrounding the defective device 15 a coincides with theopening 52 b.

Then, the liquid column 50 is formed by jetting the liquid from thelaser irradiating unit 30C, and the laser beam 32C is applied from thelaser irradiating unit 30C. At this time, the condensing point of thelaser beam 32C is positioned inside the liquid column 50. The laser beam32C is applied to the wafer 11 via the liquid column 50.

The application of the laser beam 32C to the liquid column 50 asdescribed above makes it possible to guide the laser beam 32C to thestreets 13 of the wafer 11 even when the height position of thecondensing point of the laser beam 32C is not precisely controlled. Inaddition, the liquid washes away a processing waste (debris) produced bythe laser processing.

Then, the laser beam 32C is scanned along the streets 13 together withthe liquid column 50. Consequently, the kerf 35 is formed in the wafer11 along the streets 13, and the defective device region 11 c is thusdivided from the wafer 11. Incidentally, the liquid jetted from thelaser irradiating unit 30C is discharged via the opening 52 b providedin the holding table 52.

The wafer 11 is thereafter fixed to a support substrate. FIG. 13B is asectional view depicting the wafer 11 fixed to the support substrate 23.After the kerf 35 is formed in the wafer 11 and the defective deviceregion 11 c is separated, the support substrate 23 is fixed to the topsurface 11 a side of the wafer 11 via the adhesive layer 25.

Incidentally, etching processing may be performed by supplying gasconverted into plasma or an etchant to the processed region (kerf 35)processed by the application of the laser beam 32C. Consequently, thekerf 35 is expanded, and minute projections and depressions formed onthe inner wall of the kerf 35 by the ablation processing are removed.

In addition, while a method of separating the defective device region 11c from the wafer 11 by laser processing has been described in the abovedescription, a method other than laser processing can also be used toseparate the defective device region 11 c. For example, what isgenerally called plasma dicing, which cuts the wafer 11 by plasmaetching, can also be used.

In a case where the plasma dicing is to be performed, first, the supportsubstrate 23 is fixed to the top surface 11 a side of the wafer 11 (seeFIG. 4A). A mask for plasma etching is thereafter formed on theundersurface 11 b side of the wafer 11.

FIG. 14A is a sectional view depicting the wafer 11 on which a masklayer 37 is formed. The mask layer 37 is formed of a materialfunctioning as the mask for the plasma etching, and is formed so as tocover the whole of the undersurface 11 b of the wafer 11. Usable as themask layer 37 is, for example, a resist formed of a photosensitive resinor a water-soluble resin such as PVA or PEG.

Next, a region of the mask layer 37 which coincides with the fourstreets 13 surrounding the defective device 15 a is removed. Forexample, the mask layer 37 is removed along the streets 13 byirradiating the mask layer 37 with a laser beam 56 from a laserirradiating unit 54. Incidentally, the irradiation conditions of thelaser beam 56 are set such that the mask layer 37 is removed by ablationprocessing when the mask layer 37 is irradiated with the laser beam 56.

When the mask layer 37 is irradiated with the laser beam 56 along thefour streets 13 surrounding the defective device 15 a, a rectangularopening that exposes the four streets 13 is formed in the mask layer 37.Thus, the mask layer 37 is patterned, and a mask 39 (see FIG. 14B) forplasma etching is formed.

Next, the wafer 11 is subjected to plasma etching using the mask 39. Theabove-described plasma processing apparatus, for example, is used forthe plasma etching of the wafer 11.

FIG. 14B is a sectional view depicting the wafer 11 subjected to theplasma etching. When the plasma etching is performed, gas (etching gas)58 for etching in a plasma state is supplied to the wafer 11 via theopening of the mask 39. Consequently, a region along the streets 13surrounding the defective device 15 a in the wafer 11 is etched, and agroove is formed on the undersurface 11 b side of the wafer 11.

FIG. 14C is a sectional view depicting the wafer 11 after the plasmaetching. When the etching progresses and the groove formed on theundersurface 11 b side of the wafer 11 reaches the top surface 11 a, akerf 35 extending from the top surface 11 a to the undersurface 11 b ofthe wafer 11 is formed along the streets 13, and the defective deviceregion 11 c is thus divided from the wafer 11. Thereafter, the defectivedevice region 11 c is separated from the wafer 11, and the through hole11 d is formed in the wafer 11 (see FIG. 8A, FIG. 8B, and FIG. 9).

Incidentally, the plasma etching may be performed by supplying the gas58 converted into plasma to the top surface 11 a side of the wafer 11.In this case, the mask 39 is formed on the top surface 11 a side of thewafer 11 before the wafer 11 is fixed to the support substrate 23. Then,the gas 58 is supplied to the wafer 11 via the mask 39, and a groove isformed on the top surface 11 a side of the wafer 11. When this groovereaches the undersurface 11 b, the kerf 35 is formed, and the defectivedevice region 11 c is thus divided from the wafer 11. The supportsubstrate 23 is thereafter fixed to the top surface 11 a side of thewafer 11.

After the steps as described above, the defective device region 11 c isseparated from the wafer 11, and the through hole 11 d is formed in thewafer 11. As a result, as depicted in FIG. 3B, the wafer 11 notincluding the defective device 15 a is obtained.

Next, a device chip is prepared, the device chip including asemiconductor device 15 as a non-defective product that is of the samekind as that of the semiconductor device 15 (defective device 15 a)determined to be a defective product and having such a size as to beable to be fitted into the through hole lid. A wafer having an identicalstructure to that of the wafer 11, for example, is used to manufacturethe device chip. FIG. 15A is a perspective view depicting a wafer 51 forpreparing the device chip.

The wafer 51 is formed of the same material as that of the wafer 11. Thewafer 51 includes a top surface (first surface) 51 a and an undersurface(second surface) 51 b. In addition, the wafer 51 is demarcated into aplurality of regions by a plurality of streets (planned dividing lines)53 arranged in a lattice manner so as to intersect each other. Then, asemiconductor device 55 is formed in each of the plurality of regionsdemarcated by the streets 53 on the top surface 51 a side of the wafer51.

The semiconductor device 55 has the same functions as those of thesemiconductor devices 15 depicted in FIG. 1A and the like. In addition,the structure of the semiconductor device 55 is similar to that of thesemiconductor devices 15. Electrodes (via electrodes or throughelectrodes) 57 (see FIG. 17A) are connected to the semiconductor device55. The structure and material of the electrodes 57 are similar to thoseof the electrodes 19 depicted in FIG. 1B and the like.

A plurality of device chips each including each of semiconductor devices55 are manufactured by dividing the wafer 51 along the streets 53. Thedivision of the wafer 51 is performed by the laser processing or theplasma etching described earlier, for example.

In addition, a cutting apparatus can also be used to divide the wafer51. The cutting apparatus includes a chuck table that holds the wafer 51and a cutting unit that cuts the wafer 51 held by the chuck table. Anannular cutting blade is fitted to the cutting unit. The wafer 51 isdivided along the streets 53 by rotating the cutting blade and makingthe cutting blade cut into the wafer 51. As a result, the plurality ofdevice chips each including each of the semiconductor devices 55 areobtained.

FIG. 15B is a perspective view depicting the wafer 51 divided into aplurality of device chips 59. Incidentally, before or after the divisionof the wafer 11, the plurality of semiconductor devices 55 formed in thewafer 51 are inspected to determine whether each of the semiconductordevices 55 is a non-defective product or a defective product. Then, adevice chip 59 including a semiconductor device 55 determined to be adefective product is excluded from the plurality of device chips 59obtained by the division of the wafer 51.

Consequently, the device chips 59 each including each of thesemiconductor devices 55 identical to the semiconductor devices 15 (seeFIG. 1A and the like) as non-defective products formed in the wafer 11are obtained. That is, the device chips 59 each include each of thesemiconductor devices 55 as non-defective products having the samefunctions as those of the defective device 15 a (see FIG. 1A and thelike) (the semiconductor devices 55 including the functions that shouldbe possessed by the defective device 15 a).

It is to be noted that a timing of preparing the device chips 59 is notlimited. For example, the device chips 59 are manufactured by thedivision of the wafer 51 after the preparation of the wafer 51 and theinspection of the semiconductor devices 55 are performed at the sametiming as the preparation of the wafer 11 and the inspection of thesemiconductor devices 15.

Next, a device chip 59 is fitted into the through hole 11 d of the wafer11 (fitting step). FIG. 16 is a perspective view depicting the wafer 11in the fitting step.

In a case where the top surface 11 a side (semiconductor device 15 side)of the wafer 11 is fixed to the support substrate 23, the device chip 59is positioned such that a surface side thereof on which thesemiconductor device 55 is formed (top surface side) faces the supportsubstrate 23. Then, the device chip 59 is fitted into the through hole11 d of the wafer 11.

FIG. 17A is a sectional view depicting the wafer 11 in which the devicechip 59 is fitted. The device chip 59 is fitted into the through hole 11d so as to come into contact with the adhesive layer 25 exposed withinthe through hole 11 d. The device chip 59 is thereby fixed to thesupport substrate 23 via the adhesive layer 25.

Incidentally, in a case where the wafer 11 is provisionally fixed to thesupport substrate 23 by the adhesive layer 25 and thus bonding betweenthe wafer 11 and the support substrate 23 is weak, processing of firmlyfixing the wafer 11 to the support substrate 23 (main fixing processing)is performed after the device chip 59 is fitted into the through hole 11d. The wafer 11 and the device chip 59 are thereby firmly fixed to thesupport substrate 23 via the adhesive layer 25.

For example, in a case where the adhesive layer 25 is an adhesive formedof a thermosetting resin, the thermosetting resin is cured by performingheating treatment at a higher temperature or for a longer period than atthe time of the provisional fixing, and thereby the bonding between thewafer 11 and the support substrate 23 is enhanced. In addition, in acase where the adhesive layer 25 is an adhesive formed of an ultravioletcurable resin, the bonding between the wafer 11 and the supportsubstrate 23 is enhanced by subjecting the ultraviolet curable resin toheating treatment. Further, in a case where the adhesive layer 25 is athermocompression bonding sheet, the bonding between the wafer 11 andthe support substrate 23 is enhanced by pressing the wafer 11 and thesupport substrate 23 against the thermocompression bonding sheet whileheating treatment at a higher temperature or for a longer period than atthe time of the provisional fixing is performed.

In addition, in the removing step, in a case where the wafer 11 isprovisionally fixed to the support substrate 23 by using an adhesivelayer 25 having a weak adhesive power, the wafer 11 and the supportsubstrate 23 may be temporarily separated from each other before thefitting step, and the wafer 11 may be fixed to the support substrate 23again by using another adhesive layer having a higher adhesive powerthan the adhesive layer 25.

FIG. 17B is a plan view depicting the through hole 11 d. In theforegoing removing step, the through hole 11 d is formed so as to belarger than the device chip 59. Specifically, a length L_(A1) in a firstdirection (left-right direction on a paper surface) of the through hole11 d is larger than a length L_(B1) in the first direction of the devicechip 59. In addition, a length L_(A2) in a second direction (directionperpendicular to the first direction or an upward-downward direction onthe paper surface) of the through hole 11 d is larger than a lengthL_(B2) in the second direction of the device chip 59. Therefore, whenthe device chip 59 is fitted into the through hole 11 d, a gap 61 isformed between the wafer 11 and the device chip 59 so as to surround thedevice chip 59.

Incidentally, in a subsequent step (resin filling step to be describedlater), the gap 61 is filled with a resin. Therefore, a certain width ormore is preferably secured as the width of the gap 61 (distance betweenthe inner wall of the through hole 11 d and the side surface of thedevice chip 59). For example, the size of the through hole 11 d or thedevice chip 59 is adjusted such that the width of the gap 61 is equal toor more than 2 μm, preferably equal to or more than 5 μm, or morepreferably equal to or more than 10 μm.

Concrete dimensions of the through hole 11 d can be set as appropriatein consideration of the positions of the semiconductor devices 15 and 55and the like. For example, on the top surface 11 a side of the wafer 11,a distance between an edge portion (inner wall) of the through hole 11 dand an edge portion of a semiconductor device 15 is set to be equal toor more than 2 μm, or preferably equal to or more than 5 μm. Inaddition, on the top surface 11 a side of the wafer 11, the edge portionof the through hole 11 d may be disposed more on the semiconductordevice 15 side than the center in the width direction of the street 13.In addition, in a case where the inner wall of the through hole 11 d isinclined with respect to the thickness direction of the wafer 11 asdepicted in FIG. 17A, a part of a region on the undersurface 11 b sideof the wafer 11 in the through hole 11 d may coincide with a part of thesemiconductor device 15 formed in the wafer 11.

Concrete dimensions of the device chip 59 are not limited either as longas the device chip 59 can be fitted into the through hole 11 d. Forexample, on the top surface side of the device chip 59, a distancebetween an edge portion of the semiconductor device 55 and an edgeportion of the device chip 59 is set to be equal to or less than half ofthe width of the streets 13 set on the wafer 11.

Incidentally, in the fitting step, instead of fixing the device chip 59to the adhesive layer 25, the device chip 59 having an adhesive layeradhering thereto may be fitted into the through hole 11 d. Specifically,the device chip 59 having an adhesive layer adhering thereto may befixed to the support substrate 23 via the adhesive layer after theadhesive layer 25 exposed within the through hole 11 d is removed byprocessing such as plasma etching or wet etching (chemical solutionprocessing).

FIG. 18A is a sectional view depicting the wafer 11 when the adhesivelayer 25 is subjected to plasma etching. A region superimposed on thethrough hole 11 d in the adhesive layer 25 is removed by supplying gasconverted into plasma (etching gas) 60 to the undersurface 11 b side ofthe wafer 11, for example.

FIG. 18B is a sectional view depicting the wafer 11 in a state in whicha part of the adhesive layer 25 is removed. When the region superimposedon the through hole 11 d in the adhesive layer 25 is removed, a regionsuperimposed on the through hole 11 d in the upper surface of thesupport substrate 23 is exposed. Incidentally, when the wafer 11 issubjected to the plasma etching, a mask that exposes the through hole 11d may be formed on the undersurface 11 b side of the wafer 11.

Next, the device chip 59 having an adhesive layer adhering thereto isfitted into the through hole 11 d. FIG. 18C is a sectional viewdepicting the wafer 11 in which the device chip 59 having an adhesivelayer 63 adhering thereto is fitted. The adhesive layer 63 is providedto the top surface side (semiconductor device 55 side) of the devicechip 59. Incidentally, an example of the material of the adhesive layer63 is similar to that of the adhesive layer 25. The device chip 59 isfixed to the upper surface of the support substrate 23 exposed withinthe through hole 11 d via the adhesive layer 63.

Then, after the device chip 59 is fitted into the through hole 11 d,main fixing processing is performed on the adhesive layers 25 and 63 asrequired. The wafer 11 and the device chip 59 are thereby firmly fixedto the support substrate 23 via the adhesive layers 25 and 63.

Next, a resin is filled into the gap 61 between the wafer 11 and thedevice chip 59 (resin filling step). FIG. 19A is a sectional viewdepicting the wafer 11 in the resin filling step.

In the resin filling step, a resin 65 is formed on the undersurface 11 bside of the wafer 11. The resin 65 is, for example, formed by applying aliquid resin such as an epoxy resin to the undersurface 11 b side of thewafer 11 and curing the liquid resin. However, the material of the resin65 is not limited.

When the liquid resin is applied to the undersurface 11 b side of thewafer 11, a part of the liquid resin flows into the gap 61 between thewafer 11 and the device chip 59 (see FIG. 17A, FIG. 17B, and the like),and is filled into the gap 61. When the liquid resin is cured in thisstate, the wafer 11 and the device chip 59 are coupled to each other viathe resin 65, and the device chip 59 is thus fixed to the wafer 11.

Next, the resin 65 formed on the outside of the gap 61 is ground (resingrinding step). In the resin grinding step, the resin 65 formed on theundersurface 11 b side of the wafer 11 is removed by grindingprocessing. The grinding apparatus 2 (see FIG. 2), for example, is usedto grind the resin 65.

FIG. 19B is a sectional view depicting the wafer 11 in the resingrinding step. In the resin grinding step, for example, the resin 65formed on the outside of the gap 61 is removed by grinding, and theundersurface 11 b side of the wafer 11 is ground. Then, the wafer 11 isthinned until the electrodes 19 and 57 are exposed on the undersurface11 b side of the wafer 11.

However, a method of exposing the electrodes 19 and 57 is not limited.For example, the electrodes 19 and 57 may be exposed by grinding theresin 65 until the undersurface 11 b side of the wafer 11 is exposed inthe resin grinding step, and thereafter performing etching processingsuch as plasma etching or wet etching on the undersurface 11 b side ofthe wafer 11. In this case, it is possible to prevent the metal includedin the electrodes 19 and 57 from being scattered while the grindingstones 16 (see FIG. 2) are in contact with the electrodes 19 and 57.

After the above steps, the wafer 11 having the electrodes 19 and 57exposed on the undersurface 11 b side is obtained. It is thus possibleto connect, via the electrodes 19 and 57, the semiconductor devices 15and 55 and semiconductor devices (not depicted) included in anotherwafer laminated to the undersurface 11 b side of the wafer 11. That is,the wafer manufacturing method according to the present embodimentmanufactures the wafer 11 that can be used to form a laminated wafer.

Description will next be made of a concrete example of a method ofmanufacturing device chips (laminated device chips) each including aplurality of laminated semiconductor devices by using theabove-described wafer 11. When the laminated device chips are to bemanufactured, first, a laminated wafer including a plurality oflaminated wafers is formed (wafer laminating step). FIG. 20 is asectional view depicting a laminated wafer 79.

The wafer laminating step uses the wafer 11 (first wafer) after theresin grinding step and another wafer 71 (second wafer) prepared in theabove-described wafer preparing step. Incidentally, the configuration ofthe wafer 71 is similar to that of the wafer 11.

Specifically, the wafer 71 is formed of the same material as that of thewafer 11, and has a top surface (first surface) 71 a and an undersurface(second surface) 71 b. In addition, the wafer 71 is demarcated into aplurality of rectangular regions by a plurality of streets (planneddividing lines) 73 arranged in a lattice manner so as to intersect eachother. A semiconductor device 75 is formed in each of the plurality ofregions demarcated by the streets 73 on the top surface 71 a side of thewafer 71.

The structure of the semiconductor devices 75 is similar to that of thesemiconductor devices 15. In addition, electrodes (via electrodes orthrough electrodes) 77 are connected to the semiconductor devices 75.The structure and material of the electrodes 77 are identical to thoseof the electrodes 19.

The wafer 71 is laminated onto the wafer 11. For example, the wafer 71is laminated to the wafer 11 such that the top surface 71 a side facesthe undersurface 11 b side of the wafer 11. It is to be noted that amethod of laminating the wafer 11 and the wafer 71 is not limited. Forexample, the wafer 11 and the wafer 71 are laminated by direct bonding.Specifically, the undersurface 11 b side of the wafer 11 and the topsurface 71 a side of the wafer 71 are bonded to each other by surfaceactivated bonding.

However, the wafer 11 and the wafer 71 may be bonded to each other byindirect bonding. For example, it is also possible to bond the wafer 11and the wafer 71 to each other by laminating the wafer 71 onto the wafer11 via a permanent adhesive.

Incidentally, when the plurality of semiconductor devices 75 formed inthe wafer 71 include a defective device, the wafer 71 is subjected tothe grinding step, the removing step, the fitting step, the resinfilling step, and the resin grinding step before or after the wafer 71is laminated onto the wafer 11. As a result, the defective device isremoved from the wafer 71, and a device chip 59 including asemiconductor device 55 as a non-defective product is fitted into thewafer 71.

The wafer 11 and the wafer 71 are laminated to each other such that thestreets 13 and the streets 73 are superimposed on each other and thesemiconductor devices 15 and 55 included in the wafer 11 and thesemiconductor devices 75 and 55 included in the wafer 71 aresuperimposed on each other. As a result, the semiconductor devices 15and 55 included in the wafer 11 and the semiconductor devices 75 and 55included in the wafer 71 are connected to each other via the electrodes19 and 57.

The laminated wafer 79 including the wafer 11 and the wafer 71 laminatedto each other is thus formed. Incidentally, in the wafer laminatingstep, a plurality of wafers 71 may be laminated onto the wafer 11. Forexample, yet another wafer 71 may be laminated onto the wafer 71laminated onto the wafer 11. In this case, each of the plurality ofwafers 71 laminated on the wafer 11 is subjected to the grinding step,the removing step, the fitting step, the resin filling step, and theresin grinding step. The laminated wafer 79 including three layers ormore of wafers is thereby obtained.

Next, laminated device chips each including a plurality of laminatedsemiconductor devices are formed by dividing the laminated wafer 79along the streets 13 and 73 (dividing step). FIG. 21A is a sectionalview depicting the laminated wafer 79 in the dividing step.

In the dividing step, the laminated wafer 79 is, for example, cut by acutting apparatus. The cutting apparatus includes a chuck table thatholds the laminated wafer 79 and a cutting unit that cuts the laminatedwafer 79 held by the chuck table. The cutting unit includes acylindrical spindle rotated by a rotational driving source such as amotor. Then, an annular cutting blade 62 for cutting the laminated wafer79 is fitted to a distal end portion of the spindle.

A cutting blade of a hub type (hub blade), for example, is used as thecutting blade 62. The hub blade is formed by integrating an annular baseformed of a metal or the like and an annular cutting edge formed alongthe outer circumferential edge of the base. The cutting edge of the hubblade is formed by an electroformed grindstone in which abrasive grainsformed of diamond or the like are fixed by a binding material such as anickel plating.

In addition, a cutting blade of a washer type (washer blade) can also beused as the cutting blade 62. The washer blade is formed by an annularcutting edge in which abrasive grains are fixed by a binding materialformed of a metal, ceramic, a resin, or the like.

The laminated wafer 79 is divided by rotating the cutting blade 62 andmaking the cutting blade 62 cut into the laminated wafer 79.Specifically, in a state in which a lower end of the cutting blade 62 ispositioned below the top surface 11 a of the wafer 11 (upper surface ofthe adhesive layer 25), the cutting blade 62 is made to cut into thelaminated wafer 79 along the streets 13 and 73 by moving the cuttingblade 62 and the laminated wafer 79 relative to each other along thehorizontal direction while the cutting blade 62 is rotated. Then, whenthe laminated wafer 79 is cut along all of the streets 13 and 73, thelaminated wafer 79 is divided into a plurality of laminated devicechips.

FIG. 21B is a sectional view depicting the laminated wafer 79 dividedinto a plurality of laminated device chips 81. Each of the laminateddevice chips 81 includes one semiconductor device 15 or onesemiconductor device 55 (first semiconductor device) included in thewafer 11 and one semiconductor device 75 or one semiconductor device 55(second semiconductor device) included in the wafer 71. Then, the firstsemiconductor device and the second semiconductor device are laminatedto each other, and are connected to each other via electrodes 19 orelectrodes 57.

As described above, in the wafer manufacturing method according to thepresent embodiment, the defective device region 11 c is removed from thewafer 11, and a device chip 59 including a semiconductor device 15 as anon-defective product is fitted into a space formed by removing thedefective device region 11 c (removed region). Consequently, the wafer11 not including the defective device 15 a can be manufactured. Inaddition, the laminated device chips 81 each not including the defectivedevice 15 a can be manufactured by laminating the wafer 11 not includingthe defective device 15 a, thereby forming the laminated wafer 79, anddividing the laminated wafer 79. As a result, a decrease in yield of thelaminated device chips 81 is suppressed.

Second Embodiment

In the first embodiment, description has been made of an example inwhich the defective device region 11 c is separated by the applicationof a laser beam in the removing step. However, another method may beused to separate the defective device region 11 c. In the presentembodiment, description will be made of a method of separating thedefective device region 11 c by crushing processing of crushing thewafer 11 in the removing step after performing the wafer preparing stepand the grinding step (see FIG. 2).

The crushing processing used in the present embodiment is not limited aslong as the crushing processing can process the wafer 11. Examples ofthe crushing processing that can be used to process the wafer 11 includesandblast processing, water jet processing, drill processing, and thelike.

FIG. 22A is a sectional view depicting the wafer 11 in which a groove 93is formed by the sandblast processing. A sandblast unit 72 that jets apolishing material 74 is used for the sandblast processing. Thesandblast unit 72, for example, includes a compressor that compressesand feeds gas such as air and a blast gun that jets the polishingmaterial 74 together with the compressed gas. The polishing material 74jetted from the sandblast unit 72 collides with the wafer 11. The wafer11 is thereby processed.

When the crushing processing is to be performed, first, a protectivelayer 91 is formed on the wafer 11. For example, in a case where the topsurface 11 a side of the wafer 11 is processed, the top surface 11 aside of the wafer 11 is covered by the protective layer 91 to protectthe semiconductor devices 15. It is to be noted that the material of theprotective layer 91 is not limited. A water-soluble resin such as PVA orPEG, for example, can be used as the material of the protective layer91. In addition, the formation of the protective layer 91 may be omittedin a case where damage to the semiconductor devices 15 due to thecrushing processing is not likely to occur.

Next, the wafer 11 is held by a holding table 70. The upper surface ofthe holding table 70 constitutes a flat holding surface 70 a that holdsthe wafer 11. The wafer 11 is, for example, disposed on the holdingtable 70 such that the top surface 11 a side is exposed upward and theundersurface 11 b side faces the holding surface 70 a.

Then, the polishing material 74 is jetted from the sandblast unit 72along the four streets 13 surrounding the defective device 15 a. As aresult, on the top surface 11 a side of the wafer 11, a band-shapedgroove 93 is formed along the streets 13. This groove 93 is formed in arectangular shape as viewed in plan so as to surround the defectivedevice 15 a.

FIG. 22B is a sectional view depicting the wafer 11 in which a groove 93is formed by the water jet processing. A water jet unit 76 that jets aliquid 78 such as water is used for the water jet processing. The waterjet unit 76 includes a nozzle that jets the liquid 78 pressurized by apump. Incidentally, the liquid 78 may include abrasive grains. Theliquid 78 jetted from the water jet unit 76 collides with the wafer 11.The wafer 11 is thereby processed.

Specifically, the liquid 78 jetted from the water jet unit 76 is jettedalong the four streets 13 surrounding the defective device 15 a. As aresult, on the top surface 11 a side of the wafer 11, a band-shapedgroove 93 is formed along the streets 13. This groove 93 is formed in arectangular shape as viewed in plan so as to surround the defectivedevice 15 a.

FIG. 22C is a sectional view depicting the wafer 11 in which a groove 93is formed by the drill processing. A drill unit 80 fitted with arod-shaped drill bit 82 is used for the drill processing. The drill unit80 includes a rotational driving source such as a motor that rotates thedrill bit 82 fitted to the drill unit 80. A distal end portion of thedrill bit 82 is brought into contact with the wafer 11 while the drillbit 82 is rotated. The wafer 11 is thereby processed.

Specifically, first, the rotating drill bit 82 is brought into contactwith a region of the wafer 11 which is superimposed on a street 13, anda cylindrical groove is thereby formed in the wafer 11. Next, theholding table 70 or the drill bit 82 is moved along the street 13.Incidentally, an amount of movement at this time is set to be less thanthe diameter of the cylindrical groove formed in the wafer 11.Thereafter, the drill bit 82 forms a new groove in the wafer 11. As aresult, the groove already formed in the wafer 11 and the newly formedgroove are coupled to each other.

A plurality of grooves are formed along the four streets 13 surroundingthe defective device 15 a by repeating the above-described procedure. Asa result, on the top surface 11 a side of the wafer 11, a band-shapedgroove 93 is formed along the streets 13. This groove 93 is formed by aplurality of cylindrical grooves formed so as to be coupled to eachother.

The groove 93 is formed in the wafer 11 by performing the crushingprocessing along the streets 13 surrounding the defective device 15 a asdescribed above. Thereafter, the processed region (groove 93) processedby the crushing processing is exposed on the undersurface 11 b side ofthe wafer 11 by grinding the undersurface 11 b side of the wafer 11.

When the wafer 11 is to be ground, first, the wafer 11 is fixed to thesupport substrate 23. FIG. 23A is a sectional view depicting the wafer11 fixed to the support substrate 23. In a case where the undersurface11 b side of the wafer 11 is ground, the top surface 11 a side of thewafer 11 is fixed to the support substrate 23 via the adhesive layer 25.

Next, the grinding apparatus 2 (see FIG. 2) grinds the wafer 11.Specifically, the undersurface 11 b side of the wafer 11 is ground bybringing the grinding stones 16 into contact with the undersurface 11 bside of the wafer 11. Then, the wafer 11 is ground and thinned until thegroove 93 is exposed on the undersurface 11 b side of the wafer 11.

FIG. 23B is a sectional view depicting the wafer 11 after being ground.When the groove 93 is exposed on the undersurface 11 b side of the wafer11, the defective device region 11 c is divided from the wafer 11.Thereafter, a procedure similar to that of the first embodimentseparates the defective device region 11 c from the wafer 11, and formsthe through hole 11 d in the wafer (see FIG. 8A, FIG. 8B, and FIG. 9).

Incidentally, in the removing step, the defective device region 11 c maybe separated by forming a through hole that penetrates the wafer 11 bythe crushing processing. Specifically, the crushing processing forms athrough hole extending from the top surface 11 a to the undersurface 11b of the wafer 11 along the streets 13.

FIG. 24A is a sectional view depicting the wafer 11 in which a throughhole 95 is formed by the sandblast processing. In a case where thethrough hole 95 is formed by the crushing processing, the holding table70 is provided with an opening 70 b that vertically penetrates theholding table 70. The opening 70 b is formed in a rectangular shape asviewed in plan so as to correspond to the four streets 13 surroundingthe semiconductor device 15. Then, the wafer 11 is disposed on theholding table 70 such that the four streets 13 surrounding the defectivedevice 15 a each coincide with the opening 70 b.

Next, the polishing material 74 is jetted from the sandblast unit 72along the four streets 13 surrounding the defective device 15 a.Incidentally, jetting conditions of the polishing material 74 are setsuch that a hole penetrating the wafer 11 from the top surface 11 a tothe undersurface 11 b is formed in a region of the wafer 11 with whichthe polishing material 74 collides.

Consequently, when the polishing material 74 is jetted along the streets13, a band-shaped through hole 95 extending from the top surface 11 a tothe undersurface 11 b is formed in the wafer 11 along the streets 13.This through hole 95 is formed in a rectangular shape as viewed in planso as to surround the defective device 15 a. As a result, the defectivedevice region 11 c is divided from the wafer 11.

FIG. 24B is a sectional view depicting the wafer 11 in which a throughhole 95 is formed by the water jet processing. In a case where thethrough hole 95 is formed by the water jet processing, the liquid 78jetting from the water jet unit 76 is jetted along the four streets 13surrounding the defective device 15 a. Incidentally, jetting conditionsof the liquid 78 are set such that a hole penetrating the wafer 11 fromthe top surface 11 a to the undersurface 11 b is formed in a region ofthe wafer 11 with which the liquid 78 collides.

Consequently, when the liquid 78 is jetted along the streets 13, aband-shaped through hole 95 extending from the top surface 11 a to theundersurface 11 b is formed in the wafer 11 along the streets 13. Thisthrough hole 95 is formed in a rectangular shape as viewed in plan so asto surround the defective device 15 a. As a result, the defective deviceregion 11 c is divided from the wafer 11.

FIG. 24C is a sectional view depicting the wafer 11 in which a throughhole 95 is formed by the drill processing. In a case where the throughhole 95 is formed by the drill processing, first, a cylindrical holepenetrating the wafer 11 from the top surface 11 a to the undersurface11 b is formed by bringing the drill bit 82 into contact with the wafer11 while the drill bit 82 is rotated.

Thereafter, a plurality of holes are formed along the four streets 13surrounding the defective device 15 a by repeating a similar procedure.Incidentally, each of the plurality of holes is formed so as to becoupled to a hole already formed in the wafer 11. As a result, aband-shaped through hole 95 extending from the top surface 11 a to theundersurface 11 b is formed in the wafer 11 along the streets 13, andthe defective device region 11 c is thus divided from the wafer 11.

When the sandblast processing (see FIG. 24A) is performed, the polishingmaterial 74 passed through the through hole 95 of the wafer 11 isdischarged via the opening 70 b of the holding table 70. Similarly, whenthe water jet processing (see FIG. 24B) is performed, the liquid 78passed through the through hole 95 of the wafer 11 is discharged via theopening 70 b of the holding table 70. It is therefore possible toprevent the holding table 70 from being damaged by the collision of thepolishing material 74 or the liquid 78 with the holding surface 70 a ofthe holding table 70.

In addition, when the drill processing (see FIG. 24C) is performed, adistal end portion of the drill bit 82 is inserted into the opening 70 bof the holding table 70. It is therefore possible to prevent the holdingtable 70 from being damaged by the contact of the drill bit 82 with theholding table 70.

Incidentally, while FIG. 24A, FIG. 24B, and FIG. 24C depict states inwhich the wafer 11 is processed from the top surface 11 a side, thewafer 11 may be processed from the undersurface 11 b side. That is, thepolishing material 74 or the liquid 78 may be made to collide with theundersurface 11 b side of the wafer 11, or the drill bit 82 may bebrought into contact with the undersurface 11 b side of the wafer 11.

Next, the protective layer 91 is removed from the wafer 11, and thedefective device region 11 c is separated from the wafer 11. The wafer11 is thereafter fixed to the support substrate 23. FIG. 25 is asectional view depicting the wafer 11 fixed to the support substrate 23.For example, the top surface 11 a side of the wafer 11 is fixed to thesupport substrate 23 via the adhesive layer 25.

Incidentally, the wafer 11 in which the through hole 11 d is formed bythe crushing processing may be subjected to etching processing. Forexample, the inside of the through hole 11 d is subjected to plasmaetching by supplying gas in a plasma state to the through hole 11 d ofthe wafer 11. In addition, the inside of the through hole 11 d issubjected to wet etching by supplying an etchant to the through hole 11d of the wafer 11.

FIG. 26 is a sectional view depicting the wafer 11 subjected to theplasma etching. When gas (etching gas) 84 for etching in a plasma stateis supplied to the wafer 11, the inner wall of the through hole 11 d issubjected to the plasma etching. The size of the through hole 11 d isthereby increased. In addition, minute projections and depressionsformed on the inner wall of the through hole 11 d by the crushingprocessing are removed by the plasma etching.

Incidentally, a region of the wafer 11 which is subjected to thecrushing processing is set as appropriate such that the through hole 11d of a desired size is formed. FIG. 27A is a plan view depicting aregion (processed region) 97A processed by the sandblast processing orthe water jet processing. In addition, FIG. 27B is a plan view depictingregions (processed regions) 97B processed by the drill processing. InFIG. 27A and FIG. 27B, the regions 97A and 97B are provided with apattern.

In the case where the wafer 11 is processed by the sandblast processing,the polishing material 74 is, for example, jetted to the region 97Aalong the peripheral edge of the defective device 15 a. Similarly, inthe case where the wafer 11 is processed by the water jet processing,the liquid 78 is, for example, jetted to the region 97A along theperipheral edge of the defective device 15 a. The groove 93 (see FIG.22A and FIG. 22B) or the through hole 95 (see FIG. 24A and FIG. 24B) isthereby formed so as to surround the defective device 15 a.Incidentally, the polishing material 74 and the liquid 78 may be jettedso as to collide with a part of the defective device 15 a, or may bejetted only onto the streets 13 so as not to collide with the defectivedevice 15 a.

In the case where the wafer 11 is processed by the drill processing, thedrill bit 82, for example, sequentially processes a plurality of regions97B along the peripheral edge of the defective device 15 a.Incidentally, the plurality of regions 97B are each set so as to overlapa part of another adjacent region 97. The groove 93 (see FIG. 22C) orthe through hole 95 (see FIG. 24C) is thereby formed so as to surroundthe defective device 15 a. Incidentally, the drill bit 82 may be incontact with a part of the defective device 15 a, or may be in contactwith only the streets 13 so as not to be in contact with the defectivedevice 15 a.

In addition, in the case where the wafer 11 is processed by the drillprocessing, the groove 93 or the through hole 95 may be formed by movingthe drill bit 82 in the horizontal direction along the streets 13 whilethe drill bit 82 is rotated in a state in which the drill bit 82 isinserted in the wafer 11 (see FIG. 22C and FIG. 24C). In this case, workof raising and lowering the drill bit 82 on the streets 13 a largenumber of times becomes unnecessary.

Thereafter, the inner wall of the through hole 11 d is etched bysubjecting the wafer 11 to etching processing (plasma etching or thelike, see FIG. 26). As a result, minute projections and depressionsremaining in the regions 97A and 97B subjected to the crushingprocessing are removed, and the width of the through hole 11 d isincreased. The through hole 11 d enlarged as depicted in FIG. 27A andFIG. 27B is consequently formed.

As described above, in the removing step, the crushing processing canalso separate the defective device region 11 c from the wafer 11.Incidentally, steps whose description is omitted in the presentembodiment among steps included in the removing step are similar tothose of the first embodiment. In addition, in the present embodiment,steps other than the removing step (the wafer preparing step, thegrinding step, the fitting step, the resin filling step, the resingrinding step, the wafer laminating step, the dividing step, and thelike) can be performed in a manner similar to that of the firstembodiment. Further, the present embodiment can be combined with anotherembodiment as appropriate.

Third Embodiment

In the first embodiment and the second embodiment, description has beenmade of an example in which the defective device region 11 c isseparated from the wafer 11 by processing the wafer 11 along the streets13 in the removing step. However, a method of removing the defectivedevice region 11 c from the wafer 11 is not limited. In the presentembodiment, description will be made of a method of destroying andremoving the defective device region 11 c by the application of a laserbeam in the removing step after performing the wafer preparing step andthe grinding step (see FIG. 2).

FIG. 28A is a sectional view depicting the wafer 11 irradiated with alaser beam 32D. A laser irradiating unit 30D that irradiates the wafer11 with the laser beam 32D is used in a case where the defective deviceregion 11 c is destroyed by the application of the laser beam.Incidentally, the configuration of the laser irradiating unit 30D issimilar to that of the laser irradiating unit 30A (see FIG. 4A).

However, irradiation conditions of the laser beam 32D are set such thata region of the wafer 11 which is irradiated with the laser beam 32D isremoved by ablation processing. Specifically, the wavelength of thelaser beam 32D is set such that at least a part of the laser beam 32D isabsorbed by the wafer 11. That is, the laser irradiating unit 30Dapplies the laser beam 32D of a wavelength absorbable by the wafer 11.In addition, other irradiation conditions of the laser beam 32D are alsoset such that the wafer 11 is appropriately subjected to the ablationprocessing.

For example, the laser beam 32D is applied to the top surface 11 a sideof the wafer 11. Specifically, the laser beam 32D is applied in a statein which the condensing point of the laser beam 32D is positioned on theinside of the four streets 13 surrounding the defective device 15 a. Thedefective device region 11 c is thereby subjected to the ablationprocessing, so that the defective device region 11 c is destroyed. As aresult, a groove (recessed portion) is formed on the top surface 11 aside of the wafer 11.

FIG. 28B is a sectional view depicting the wafer 11 in which a groove(removed region) 101 is formed. The laser beam 32D is, for example,scanned so as to be applied over the whole of a rectangular region asviewed in plan which is located on the inside of the four streets 13surrounding the defective device 15 a. As a result, the ablationprocessing forms the groove 101 in a rectangular parallelepipedic shapeon the top surface 11 a side of the wafer 11. Incidentally, the depth ofthe groove 101 is adjusted such that the bottom surface of the groove101 is formed below lower ends of the electrodes 19. As a result, thedefective device 15 a and the electrodes 19 are removed.

FIG. 29 is a plan view depicting paths 34D along which the laser beam32D is scanned. A plurality of paths 34D going from one end side toanother end side of the defective device region 11 c, for example, areset. Then, the laser beam 32D is scanned along the paths 34D so as toreciprocate between one end and another end of the defective deviceregion 11 c. Consequently, the whole of the defective device region 11 cis irradiated with the laser beam 32D, and the defective device region11 c is removed. However, the scanning path of the laser beam 32D is notlimited as long as the defective device region 11 c can be removed.

Incidentally, when the groove 101 is to be formed, the top surface 11 aside of the wafer 11 may be covered by a protective film, and the wafer11 may be irradiated with the laser beam 32D via the protective film.Usable as the protective film is, for example, a tape made of a resin ora film formed of a water-soluble resin such as PVA or PEG. When theprotective film is formed on the top surface 11 a side of the wafer 11,a processing waste (debris) produced at the time of the ablationprocessing can be prevented from adhering to the top surface 11 a of thewafer 11, so that contamination of the wafer 11 and the semiconductordevices 15 is avoided.

Next, the processed region (groove 101) processed by the application ofthe laser beam 32D is exposed on the undersurface 11 b side of the wafer11 by grinding the undersurface 11 b side of the wafer 11. When thewafer 11 is to be ground, first, the wafer 11 is fixed to the supportsubstrate. FIG. 30A is a sectional view depicting the wafer 11 fixed tothe support substrate 23.

In a case where the undersurface 11 b side of the wafer 11 is ground,the top surface 11 a side of the wafer 11 is fixed to the supportsubstrate 23 via the adhesive layer 25.

Next, the grinding apparatus 2 (see FIG. 2) grinds the wafer 11.Specifically, the undersurface 11 b side of the wafer 11 is ground bybringing the grinding stones 16 into contact with the undersurface 11 bside of the wafer 11. Then, the wafer 11 is ground and thinned until thegroove 101 is exposed on the undersurface 11 b side of the wafer 11.

FIG. 30B is a sectional view depicting the wafer 11 after being ground.When the groove 101 is exposed on the undersurface 11 b side of thewafer 11, the through hole 11 d extending from the top surface 11 a tothe undersurface 11 b is formed in the wafer 11.

Incidentally, in the removing step, the through hole 11 d may be formeddirectly by the application of the laser beam 32D. Specifically, thethrough hole 11 d extending from the top surface 11 a to theundersurface 11 b of the wafer 11 is formed by ablation processing.

FIG. 31A is a sectional view depicting the wafer 11 irradiated with thelaser beam 32D. First, a protective member 103 such as a tape is affixedto the wafer 11. In a case where the laser beam 32D is applied to thetop surface 11 a side of the wafer 11, for example, the protectivemember 103 is affixed to the undersurface 11 b side of the wafer 11.Incidentally, an example of the material of the protective member 103 issimilar to that of the protective member 21 (see FIG. 2).

Then, the laser beam 32D is applied in a state in which the condensingpoint of the laser beam 32D is positioned on the inside of the fourstreets 13 surrounding the defective device 15 a. It is to be noted thatthe scanning path of the laser beam 32D is not limited. For example, thelaser beam 32D is scanned along the paths 34D depicted in FIG. 29.

Irradiation conditions of the laser beam 32D are set such that a regionextending from the top surface 11 a to the undersurface 11 b of thewafer 11 is removed by the ablation processing. Therefore, when theapplication of the laser beam 32D to the wafer 11 is completed, thethrough hole 11 d penetrating the wafer 11 from the top surface 11 a tothe undersurface 11 b is formed.

The wafer 11 is thereafter fixed to the support substrate. FIG. 31B is asectional view depicting the wafer 11 fixed to the support substrate 23.After the through hole 11 d is formed in the wafer 11, the supportsubstrate 23 is fixed to the top surface 11 a side of the wafer 11 viathe adhesive layer 25. The protective member 103 is thereafter peeledfrom the undersurface 11 b side of the wafer 11.

Incidentally, a laser beam (aqua laser) applied via a liquid can also beused to form the through hole 11 d. In this case, a jetting unit thatjets the liquid to the laser irradiating unit 30D is provided. Then, theliquid column 50 (see FIG. 13A) is formed by jetting the liquid from thelaser irradiating unit 30D, and the laser beam 32D is applied from thelaser irradiating unit 30D. At this time, the condensing point of thelaser beam 32D is positioned inside the liquid column 50. The laser beam32D is applied to the defective device region 11 c via the liquid column50. The defective device region 11 c is thereby removed.

In addition, the wafer 11 in which the through hole 11 d is formed bydestroying the defective device region 11 c (see FIG. 30B and FIG. 31A)may be subjected to etching processing. For example, the inside of thethrough hole 11 d is subjected to plasma etching by supplying gas in aplasma state to the through hole 11 d of the wafer 11. In addition, theinside of the through hole 11 d is subjected to wet etching by supplyingan etchant to the through hole 11 d of the wafer 11.

As described above, in the removing step, it is also possible to removethe defective device region 11 c from the wafer 11 by destroying thedefective device region 11 c by the application of the laser beam.Incidentally, steps whose description is omitted in the presentembodiment among steps included in the removing step are similar tothose of the first embodiment. In addition, in the present embodiment,steps other than the removing step (the wafer preparing step, thegrinding step, the fitting step, the resin filling step, the resingrinding step, the wafer laminating step, the dividing step, and thelike) can be performed in a manner similar to that of the firstembodiment. Further, the present embodiment can be combined with anotherembodiment as appropriate.

Fourth Embodiment

In the third embodiment, description has been made of an example inwhich the defective device region 11 c is destroyed by the applicationof the laser beam in the removing step. However, a method of destroyingthe defective device region 11 c is not limited. In the presentembodiment, description will be made of a method of destroying andremoving the defective device region 11 c by crushing processing in theremoving step after performing the wafer preparing step and the grindingstep (see FIG. 2).

The crushing processing used in the present embodiment is not limited aslong as the crushing processing can process the wafer 11. In thefollowing, description will be made of sandblast processing using thesandblast unit 72 (see FIG. 22A and the like), water jet processingusing the water jet unit 76 (see FIG. 22B and the like), and drillprocessing using the drill unit 80 (see FIG. 22C and the like) asconcrete examples of the crushing processing.

FIG. 32 is a sectional view depicting the wafer 11 held by the holdingtable 70. When the crushing processing is to be performed, first, aprotective layer 91 is formed on the wafer 11. In a case where theprocessing is performed from the top surface 11 a side of the wafer 11,for example, the top surface 11 a side of the wafer 11 is covered by theprotective layer 91. The semiconductor devices 15 are thereby protected.Incidentally, the formation of the protective layer 91 may be omitted ina case where damage to the semiconductor devices 15 due to the crushingprocessing is not likely to occur.

Next, the wafer 11 is held by the holding table 70. For example, thewafer 11 is disposed on the holding table 70 such that the top surface11 a side is exposed upward and the undersurface 11 b side faces theholding surface 70 a. Then, the wafer 11 held by the holding table 70 issubjected to the crushing processing.

FIG. 33A is a sectional view depicting the wafer 11 from which thedefective device region 11 c is removed by the sandblast processing. Ina case where the sandblast processing is performed, the polishingmaterial 74 is jetted from the sandblast unit 72 to the inside of thefour streets 13 surrounding the defective device 15 a (see FIG. 32). Asa result, a region of the wafer 11 with which the polishing material 74collides is destroyed, and a groove (removed region) 105 in arectangular parallelepipedic shape is formed on the top surface 11 aside of the wafer 11.

FIG. 33B is a sectional view depicting the wafer 11 from which thedefective device region 11 c is removed by the water jet processing. Ina case where the water jet processing is performed, a pressurized liquid78 is jetted from the water jet unit 76 to the inside of the fourstreets 13 surrounding the defective device 15 a (see FIG. 32). As aresult, a region of the wafer 11 with which the liquid 78 collides isdestroyed, and a groove 105 in a rectangular parallelepipedic shape isformed on the top surface 11 a side of the wafer 11.

Incidentally, the groove 105 is formed at least over the whole of theregion in which the defective device 15 a is formed. In addition, thedepth of the groove 105 is adjusted such that the bottom surface of thegroove 105 is formed below lower ends of the electrodes 19. As a result,the defective device 15 a and the electrodes 19 are removed.

FIG. 33C is a sectional view depicting the wafer 11 from which thedefective device region 11 c is removed by the drill processing. In acase where the drill processing is performed, the drill bit 82 beingrotated is brought into contact with the inside of the four streets 13surrounding the defective device 15 a (see FIG. 32), and a plurality ofcolumnar grooves are formed in the wafer 11. Incidentally, the pluralityof grooves are formed so as to be coupled to each other over the wholeof the region in which the defective device 15 a is formed. In addition,the depth of each of the plurality of grooves is adjusted such that thebottom surface of the groove 105 is formed below lower ends of theelectrodes 19. As a result, the groove 105 constituted by the pluralityof grooves coupled to each other is formed on the top surface 11 a sideof the wafer 11, and the defective device 15 a and the electrodes 19 areremoved.

As described above, the defective device 15 a is destroyed by performingthe crushing processing on the inside of the streets 13 surrounding thedefective device 15 a. The defective device 15 a is thereby removed fromthe wafer 11.

Next, the processed region (groove 105) processed by the crushingprocessing is exposed on the undersurface 11 b side of the wafer 11 bygrinding the undersurface 11 b side of the wafer 11. When the wafer 11is to be ground, first, the wafer 11 is fixed to the support substrate23. FIG. 34A is a sectional view depicting the wafer 11 fixed to thesupport substrate 23. In a case where the undersurface 11 b side of thewafer 11 is ground, the top surface 11 a side of the wafer 11 is fixedto the support substrate 23 via the adhesive layer 25.

Next, the grinding apparatus 2 (see FIG. 2) grinds the wafer 11.Specifically, the undersurface 11 b side of the wafer 11 is ground bybringing the grinding stones 16 into contact with the undersurface 11 bside of the wafer 11. Then, the wafer 11 is ground and thinned until thegroove 105 is exposed on the undersurface 11 b side of the wafer 11.

FIG. 34B is a sectional view depicting the wafer 11 after being ground.When the groove 105 is exposed on the undersurface 11 b side of thewafer 11, a rectangular parallelepipedic through hole 11 d extendingfrom the top surface 11 a to the undersurface 11 b is formed in thewafer 11.

Incidentally, in the removing step, the through hole 11 d may be formeddirectly by the crushing processing. Specifically, the through hole 11 dextending from the top surface 11 a to the undersurface 11 b of thewafer 11 is formed by the crushing processing.

FIG. 35A is a sectional view depicting the wafer 11 in which the throughhole 11 d is formed by the sandblast processing. In a case where thethrough hole 11 d is formed in the wafer 11 by the crushing processing,the holding table 70 is provided with an opening 70 c that verticallypenetrates the holding table 70. Then, the wafer 11 is disposed on theholding table 70 such that a region inside the four streets 13surrounding the defective device 15 a coincides with the opening 70 c.

Next, the polishing material 74 from the sandblast unit 72 is jettedover the whole of the region inside the four streets 13 surrounding thedefective device 15 a (see FIG. 32). Incidentally, jetting conditions ofthe polishing material 74 are set such that the region of the wafer 11with which the polishing material 74 collides is removed, the regionbeing from the top surface 11 a to the undersurface 11 b. As a result,the defective device region 11 c is removed, and the through hole 11 dis formed in the wafer 11.

FIG. 35B is a sectional view depicting the wafer 11 in which the throughhole 11 d is formed by the water jet processing. In a case where thewater jet processing is performed, the liquid 78 jetted from the waterjet unit 76 is jetted over the whole of the region inside the fourstreets 13 surrounding the defective device 15 a (see FIG. 32).Incidentally, jetting conditions of the liquid 78 are set such that theregion of the wafer 11 with which the liquid 78 collides is removed, theregion being from the top surface 11 a to the undersurface lib. As aresult, the defective device region 11 c is removed, and the throughhole 11 d is formed in the wafer 11.

FIG. 35C is a sectional view depicting the wafer 11 in which the throughhole 11 d is formed by the drill processing. In a case where the drillprocessing is performed, the drill bit 82 being rotated is brought intocontact with the inside of the four streets 13 surrounding the defectivedevice 15 a (see FIG. 32), and a plurality of columnar grooves areformed in the wafer 11.

The drill bit 82 processes the wafer 11 until a lower end of the drillbit 82 reaches the undersurface 11 b of the wafer 11. As a result, theplurality of grooves are formed so as to each penetrate the wafer 11from the top surface 11 a to the undersurface 11 b. In addition, theplurality of grooves are formed so as to be coupled to each other atleast over the whole of the region in which the defective device 15 a isformed. As a result, the through hole 11 d constituted by the pluralityof grooves coupled to each other is formed.

Incidentally, when the sandblast processing (see FIG. 35A) is performed,the polishing material 74 passed through the through hole 11 d of thewafer 11 is discharged via the opening 70 c of the holding table 70.Similarly, when the water jet processing (see FIG. 35B) is performed,the liquid 78 passed through the through hole 11 d of the wafer 11 isdischarged via the opening 70 c of the holding table 70. It is thereforepossible to prevent the holding table 70 from being damaged by thecollision of the polishing material 74 or the liquid 78 with the holdingsurface 70 a of the holding table 70.

In addition, when the drill processing (see FIG. 35C) is performed, adistal end portion of the drill bit 82 is inserted into the opening 70 cof the holding table 70. It is therefore possible to prevent the holdingtable 70 from being damaged by the contact of the drill bit 82 with theholding table 70.

Incidentally, while FIG. 35A, FIG. 35B, and FIG. 35C depict states inwhich the wafer 11 is processed from the top surface 11 a side, thewafer 11 may be processed from the undersurface 11 b side. That is, thepolishing material 74 or the liquid 78 may be made to collide with theundersurface 11 b side of the wafer 11, or the drill bit 82 may bebrought into contact with the undersurface 11 b side of the wafer 11.

Thereafter, the wafer 11 from which the defective device region 11 c isremoved and in which the through hole 11 d is formed is fixed to thesupport substrate 23. FIG. 36 is a sectional view depicting the wafer 11fixed to the support substrate 23. For example, the top surface 11 aside of the wafer 11 is fixed to the support substrate 23 via theadhesive layer 25.

Incidentally, the wafer 11 in which the through hole 11 d is formed bythe crushing processing may be subjected to etching processing. Forexample, the inside of the through hole 11 d is subjected to plasmaetching by supplying gas in a plasma state to the through hole 11 d ofthe wafer 11 (see FIG. 26). In addition, the inside of the through hole11 d is subjected to wet etching by supplying an etchant to the throughhole 11 d of the wafer 11. The etching processing performed on the wafer11 increases the size of the through hole 11 d, and removes minuteprojections and depressions formed on the inner wall of the through hole11 d by the crushing processing.

The region of the wafer 11 which is subjected to the crushing processingis set as appropriate such that the through hole 11 d is formed at leaston the inside of the four streets 13 surrounding the defective device 15a (see FIG. 32). FIG. 37A is a plan view depicting a region (processedregion) 97C processed by the sandblast processing or the water jetprocessing. In addition, FIG. 37B is a plan view depicting regions(processed regions) 97D processed by the drill processing. In FIG. 37Aand FIG. 37B, the regions 97C and 97D are provided with a pattern.

In the case where the wafer 11 is processed by the sandblast processing,the polishing material 74 is jetted to the region 97C including thewhole of the defective device 15 a. Similarly, in the case where thewafer 11 is processed by the water jet processing, the liquid 78 is, forexample, jetted to the region 97C including the whole of the defectivedevice 15 a. The groove 105 (see FIG. 33A and FIG. 33B) or the throughhole 11 d (see FIG. 35A and FIG. 35B) is thereby formed such that thedefective device 15 a is removed. Incidentally, the polishing material74 and the liquid 78 may be jetted so as to collide with a part of thestreets 13 surrounding the defective device 15 a.

In the case where the wafer 11 is processed by the drill processing, thedrill bit 82 sequentially processes a plurality of regions 97Doverlapping the defective device 15 a. Incidentally, the plurality ofregions 97D are set so as to each overlap a part of another adjacentregion 97D. The groove 105 (see FIG. 33C) or the through hole 11 d (seeFIG. 35C) is thereby formed such that the defective device 15 a isremoved. Incidentally, the drill bit 82 may be in contact with a part ofthe streets 13 surrounding the defective device 15 a.

In addition, in the case where the wafer 11 is processed by the drillprocessing, the groove 105 or the through hole 11 d may be formed bymoving the drill bit 82 in the horizontal direction while the drill bit82 is rotated in a state in which the drill bit 82 is inserted in thewafer 11 (see FIG. 33C and FIG. 35C). In this case, work of raising andlowering the drill bit 82 a large number of times becomes unnecessary.

Thereafter, the inner wall of the through hole 11 d is etched bysubjecting the wafer 11 to etching processing (plasma etching or thelike, see FIG. 26). As a result, minute projections and depressionsremaining in the regions 97C and 97D subjected to the crushingprocessing are removed, and the width of the through hole 11 d isincreased. The through hole 11 d enlarged as depicted in FIG. 37A andFIG. 37B is consequently formed.

As described above, in the removing step, it is also possible to removethe defective device region 11 c from the wafer 11 by destroying thedefective device region 11 c by the crushing processing. Incidentally,steps whose description is omitted in the present embodiment among stepsincluded in the removing step are similar to those of the firstembodiment. In addition, in the present embodiment, steps other than theremoving step (the wafer preparing step, the grinding step, the fittingstep, the resin filling step, the resin grinding step, the waferlaminating step, the dividing step, and the like) can be performed in amanner similar to that of the first embodiment. Further, the presentembodiment can be combined with another embodiment as appropriate.

Fifth Embodiment

In the present embodiment, description will be made of relation betweenthe step of removing the defective device region 11 c from the wafer 11(removing step) and the step of fixing the wafer 11 to the supportsubstrate 23 (support substrate fixing step). Specifically, in thepresent embodiment, detailed description will be made of a process inwhich the wafer 11 is fixed to the support substrate 23 after thedefective device region 11 c is removed from the wafer 11.

First, the wafer 11 prepared in the preparing step is subjected togrinding processing (see FIG. 2) as required (grinding step). Then, thedefective device region 11 c is removed from the wafer 11 by subjectingthe wafer 11 to processing such as laser processing or crushingprocessing (removing step). Thereafter, the wafer 11 from which thedefective device region 11 c is removed and in which the through hole 11d is formed is fixed to the support substrate 23 (support substratefixing step).

The laser processing can be used to remove the defective device region11 c. For example, the defective device region 11 c is separated fromthe wafer 11 by the laser processing (see FIG. 12A, FIG. 13A, and thelike), and the wafer 11 is thereafter fixed to the support substrate 23(see FIG. 12B, FIG. 13B, and the like). In addition, for example, thedefective device region 11 c is destroyed by the laser processing (seeFIG. 31A and the like), and the wafer 11 is thereafter fixed to thesupport substrate 23 (see FIG. 31B and the like).

In addition, the crushing processing can also be used to remove thedefective device region 11 c. For example, the defective device region11 c is separated from the wafer 11 by the crushing processing (see FIG.24A, FIG. 24B, FIG. 24C, and the like), and the wafer 11 is thereafterfixed to the support substrate 23 (see FIG. 25 and the like). Inaddition, for example, the defective device region 11 c is destroyed bythe crushing processing (see FIG. 35A, FIG. 35B, FIG. 35C, and thelike), and the wafer 11 is thereafter fixed to the support substrate 23(see FIG. 36 and the like).

Then, the device chip 59 is fitted into the through hole 11 d of thewafer 11 fixed to the support substrate 23 (fitting step, see FIGS. 16to 18C and the like). The wafer 11 not including the defective device 15a is thereby manufactured.

As described above, in a case where the support substrate fixing step isperformed after the removing step is performed, the defective deviceregion 11 c is already removed from the wafer 11 at a time point atwhich the wafer 11 is fixed to the support substrate 23. Therefore, theprocessing for removing the defective device region 11 c does not needto be performed after the wafer 11 is fixed to the support substrate 23.It is thereby possible to avoid adhesion of a waste (processing waste)produced by the processing of the wafer 11 to the support substrate 23,and prevent the processing waste adhering to the support substrate 23from obstructing the fitting of the device chip 59 into the through hole11 d.

It is to be noted that there is no limitation on a method of fixing thewafer 11 to the support substrate 23. For example, the wafer 11 is fixedto the support substrate 23 via the adhesive layer 25. As describedearlier, usable as the adhesive layer 25 is, for example, an adhesiveformed of a thermosetting resin, an adhesive formed of a thermoplasticresin, an adhesive formed of an ultraviolet curable resin, a sheetcapable of being fixed to the wafer 11 and the support substrate 23 byheating and pressurization and not including an adhesive(thermocompression bonding sheet), a tape including a thermally foamedlayer, or the like.

Thereafter, the resin filling step (see FIG. 19A), the resin grindingstep (see FIG. 19B), the wafer laminating step (see FIG. 20), and thedividing step (see FIG. 21A) are performed in order. The laminateddevice chips 81 each including a plurality of laminated semiconductordevices are thereby manufactured (see FIG. 21B).

As described above, by performing the support substrate fixing stepafter performing the removing step, it is possible to prevent adhesionof a processing waste to the support substrate 23, and perform work offitting the device chip 59 into the wafer 11 smoothly. Incidentally,steps whose description is omitted in the present embodiment among stepsincluded in the removing step and the support substrate fixing step aresimilar to those of the first embodiment. In addition, in the presentembodiment, steps other than the removing step and the support substratefixing step (the wafer preparing step, the grinding step, the fittingstep, the resin filling step, the resin grinding step, the waferlaminating step, the dividing step, and the like) can be performed in amanner similar to that of the first embodiment. Further, the presentembodiment can be combined with another embodiment as appropriate.

Sixth Embodiment

In the present embodiment, description will be made of relation betweenthe step of removing the defective device region 11 c from the wafer 11(removing step) and the step of fixing the wafer 11 to the supportsubstrate 23 (support substrate fixing step). Specifically, in thepresent embodiment, detailed description will be made of a process inwhich the defective device region 11 c is removed from the wafer 11after the wafer 11 is fixed to the support substrate 23.

First, the wafer 11 prepared in the preparing step is subjected togrinding processing (see FIG. 2) as required (grinding step). Then, thewafer 11 is fixed to the support substrate 23 (support substrate fixingstep). Thereafter, the defective device region 11 c is removed from thewafer 11 by subjecting the wafer 11 to processing such as laserprocessing or crushing processing (removing step).

The laser processing can be used to remove the defective device region11 c. For example, the wafer 11 fixed to the support substrate 23 issubjected to the laser processing (see FIG. 4A and the like), and thedefective device region 11 c is thereafter separated from the wafer 11(see FIG. 8B and the like). In addition, for example, the wafer 11 fixedto the support substrate 23 is subjected to plasma etching (see FIG. 14Band the like), and the defective device region 11 c is thereafterremoved from the wafer 11 (see FIG. 8B and the like).

In addition, for example, the wafer 11 in which a groove is formed bythe laser processing, the crushing processing, or the like is fixed tothe support substrate 23 (see FIG. 11A, FIG. 23A, and the like).Thereafter, the defective device region 11 c is removed from the wafer11 by grinding the wafer 11 (see FIG. 11B, FIG. 23B, and the like).

It is to be noted that there is no limitation on a method of fixing thewafer 11 to the support substrate 23. For example, the wafer 11 is fixedto the support substrate 23 via the adhesive layer 25. As describedearlier, usable as the adhesive layer 25 is, for example, an adhesiveformed of a thermosetting resin, an adhesive formed of a thermoplasticresin, an adhesive formed of an ultraviolet curable resin, a sheetcapable of being fixed to the wafer 11 and the support substrate 23 byheating and pressurization and not including an adhesive(thermocompression bonding sheet), a tape including a thermally foamedlayer, or the like.

Then, the device chip 59 is fitted into the through hole 11 d of thewafer 11 fixed to the support substrate 23 (fitting step, see FIGS. 16to 18C). The wafer 11 not including the defective device 15 a is therebymanufactured.

As described above, in a case where the removing step is performed afterthe support substrate fixing step is performed, the wafer 11 issupported by the support substrate 23 in a stage in which the defectivedevice region 11 c is removed from the wafer 11. Therefore, the fittingstep can be thereafter performed in succession, and the fitting of thedevice chip 59 can be performed smoothly.

In addition, in the case where the removing step is performed after thesupport substrate fixing step is performed, the grinding processing fordividing the defective device region 11 c from the wafer 11 (see FIG.11B, FIG. 23B, and the like) is performed after the work of fixing thewafer 11 to the support substrate 23. It therefore becomes unnecessaryto perform work of transporting the wafer 11 in a state of being thinnedand thus being susceptible to deformation and laminating the wafer 11 tothe support substrate 23. It is thus possible to improve work efficiencyand prevent damage to the wafer.

Thereafter, the resin filling step (see FIG. 19A), the resin grindingstep (see FIG. 19B), the wafer laminating step (see FIG. 20), and thedividing step (see FIG. 21A) are performed in order. The laminateddevice chips 81 each including a plurality of laminated semiconductordevices are thereby manufactured (see FIG. 21B).

As described above, by performing the removing step after performing thesupport substrate fixing step, it is possible to proceed smoothly to thefitting step to be thereafter performed. Incidentally, steps whosedescription is omitted in the present embodiment among steps included inthe support substrate fixing step and the removing step are similar tothose of the first embodiment. In addition, in the present embodiment,steps other than the support substrate fixing step and the removing step(the wafer preparing step, the grinding step, the fitting step, theresin filling step, the resin grinding step, the wafer laminating step,the dividing step, and the like) can be performed in a manner similar tothat of the first embodiment. Further, the present embodiment can becombined with another embodiment as appropriate.

It is to be noted that structures, methods, and the like according toeach of the foregoing embodiments can be modified and implemented asappropriate without departing from the objective scope of the presentinvention.

The present invention is not limited to the details of the abovedescribed preferred embodiments. The scope of the invention is definedby the appended claims and all changes and modifications as fall withinthe equivalence of the scope of the claims are therefore to be embracedby the invention.

What is claimed is:
 1. A wafer manufacturing method comprising: a waferpreparing step of preparing a wafer including a semiconductor deviceformed in each of a plurality of regions demarcated by a plurality ofstreets intersecting each other; a removing step of removing, from thewafer, a defective device region including a semiconductor devicedetermined to be a defective product among a plurality of thesemiconductor devices formed in the wafer; a support substrate fixingstep of fixing the wafer to a support substrate, after the removing stepis performed; and a fitting step of fitting, into a removed regionformed by removing the defective device region from the wafer, a devicechip including a semiconductor device as a non-defective product havingsame functions as those of the semiconductor device determined to be adefective product and having a size capable of being fitted into theremoved region, and fixing the device chip to the support substrate,after the support substrate fixing step is performed.
 2. The wafermanufacturing method according to claim 1, wherein the support substratefixing step fixes the wafer to the support substrate by an adhesiveformed of a thermosetting resin.
 3. The wafer manufacturing methodaccording to claim 1, wherein the support substrate has a property oftransmitting ultraviolet rays, and the support substrate fixing stepfixes the wafer to the support substrate by an adhesive formed of anultraviolet curable resin.
 4. The wafer manufacturing method accordingto claim 1, wherein the support substrate fixing step fixes the wafer tothe support substrate by pressing the wafer against the supportsubstrate via a sheet not including an adhesive while heating the sheet.5. The wafer manufacturing method according to claim 1, furthercomprising: a resin filling step of filling a resin into a gap betweenthe device chip and the wafer, after the fitting step is performed; anda resin grinding step of grinding the resin formed on an outside of thegap, after the resin filling step is performed.
 6. A laminated devicechip manufacturing method comprising: a wafer preparing step ofpreparing a first wafer and a second wafer each having a semiconductordevice formed in each of a plurality of regions demarcated by aplurality of streets intersecting each other; a removing step ofremoving, from the first wafer, a defective device region including asemiconductor device determined to be a defective product among aplurality of the semiconductor devices formed in the first wafer; asupport substrate fixing step of fixing the first wafer to a supportsubstrate, after the removing step is performed; a fitting step offitting, into a removed region formed by removing the defective deviceregion from the first wafer, a device chip including a semiconductordevice as a non-defective product having same functions as those of thesemiconductor device determined to be a defective product and having asize capable of being fitted into the removed region, and fixing thedevice chip to the support substrate, after the support substrate fixingstep is performed; a wafer laminating step of forming a laminated waferby laminating the second wafer onto the first wafer; and a dividing stepof forming laminated device chips including a plurality of the laminatedsemiconductor devices by dividing the laminated wafer along the streets.7. The laminated device chip manufacturing method according to claim 6,wherein the wafer laminating step directly bonds the first wafer and thesecond wafer to each other.